summaryrefslogtreecommitdiffstats
path: root/fs/btrfs
Commit message (Collapse)AuthorAgeFilesLines
* btrfs: bugfix: handle FS_IOC32_{GETFLAGS,SETFLAGS,GETVERSION} in btrfs_ioctlLuke Dashjr2016-06-034-2/+24
| | | | | | | | | | | | | | | [ Upstream commit 4c63c2454eff996c5e27991221106eb511f7db38 ] 32-bit ioctl uses these rather than the regular FS_IOC_* versions. They can be handled in btrfs using the same code. Without this, 32-bit {ch,ls}attr fail. Signed-off-by: Luke Dashjr <luke-jr+git@utopios.org> Cc: stable@vger.kernel.org Reviewed-by: Josef Bacik <jbacik@fb.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
* Btrfs: fix list transaction->pending_ordered corruptionFilipe Manana2016-04-221-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit d3efe08400317888f559bbedf0e42cd31575d0ef ] When we call btrfs_commit_transaction(), we splice the list "ordered" of our transaction handle into the transaction's "pending_ordered" list, but we don't re-initialize the "ordered" list of our transaction handle, this means it still points to the same elements it used to before the splice. Then we check if the current transaction's state is >= TRANS_STATE_COMMIT_START and if it is we end up calling btrfs_end_transaction() which simply splices again the "ordered" list of our handle into the transaction's "pending_ordered" list, leaving multiple pointers to the same ordered extents which results in list corruption when we are iterating, removing and freeing ordered extents at btrfs_wait_pending_ordered(), resulting in access to dangling pointers / use-after-free issues. Similarly, btrfs_end_transaction() can end up in some cases calling btrfs_commit_transaction(), and both did a list splice of the transaction handle's "ordered" list into the transaction's "pending_ordered" without re-initializing the handle's "ordered" list, resulting in exactly the same problem. This produces the following warning on a kernel with linked list debugging enabled: [109749.265416] ------------[ cut here ]------------ [109749.266410] WARNING: CPU: 7 PID: 324 at lib/list_debug.c:59 __list_del_entry+0x5a/0x98() [109749.267969] list_del corruption. prev->next should be ffff8800ba087e20, but was fffffff8c1f7c35d (...) [109749.287505] Call Trace: [109749.288135] [<ffffffff8145f077>] dump_stack+0x4f/0x7b [109749.298080] [<ffffffff81095de5>] ? console_unlock+0x356/0x3a2 [109749.331605] [<ffffffff8104b3b0>] warn_slowpath_common+0xa1/0xbb [109749.334849] [<ffffffff81260642>] ? __list_del_entry+0x5a/0x98 [109749.337093] [<ffffffff8104b410>] warn_slowpath_fmt+0x46/0x48 [109749.337847] [<ffffffff81260642>] __list_del_entry+0x5a/0x98 [109749.338678] [<ffffffffa053e8bf>] btrfs_wait_pending_ordered+0x46/0xdb [btrfs] [109749.340145] [<ffffffffa058a65f>] ? __btrfs_run_delayed_items+0x149/0x163 [btrfs] [109749.348313] [<ffffffffa054077d>] btrfs_commit_transaction+0x36b/0xa10 [btrfs] [109749.349745] [<ffffffff81087310>] ? trace_hardirqs_on+0xd/0xf [109749.350819] [<ffffffffa055370d>] btrfs_sync_file+0x36f/0x3fc [btrfs] [109749.351976] [<ffffffff8118ec98>] vfs_fsync_range+0x8f/0x9e [109749.360341] [<ffffffff8118ecc3>] vfs_fsync+0x1c/0x1e [109749.368828] [<ffffffff8118ee1d>] do_fsync+0x34/0x4e [109749.369790] [<ffffffff8118f045>] SyS_fsync+0x10/0x14 [109749.370925] [<ffffffff81465197>] system_call_fastpath+0x12/0x6f [109749.382274] ---[ end trace 48e0d07f7c03d95a ]--- On a non-debug kernel this leads to invalid memory accesses, causing a crash. Fix this by using list_splice_init() instead of list_splice() in btrfs_commit_transaction() and btrfs_end_transaction(). Cc: stable@vger.kernel.org Fixes: 50d9aa99bd35 ("Btrfs: make sure logged extents complete in the current transaction V3" Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
* Btrfs: fix file/data loss caused by fsync after rename and new inodeFilipe Manana2016-04-201-0/+137
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit 56f23fdbb600e6087db7b009775b95ce07cc3195 ] If we rename an inode A (be it a file or a directory), create a new inode B with the old name of inode A and under the same parent directory, fsync inode B and then power fail, at log tree replay time we end up removing inode A completely. If inode A is a directory then all its files are gone too. Example scenarios where this happens: This is reproducible with the following steps, taken from a couple of test cases written for fstests which are going to be submitted upstream soon: # Scenario 1 mkfs.btrfs -f /dev/sdc mount /dev/sdc /mnt mkdir -p /mnt/a/x echo "hello" > /mnt/a/x/foo echo "world" > /mnt/a/x/bar sync mv /mnt/a/x /mnt/a/y mkdir /mnt/a/x xfs_io -c fsync /mnt/a/x <power failure happens> The next time the fs is mounted, log tree replay happens and the directory "y" does not exist nor do the files "foo" and "bar" exist anywhere (neither in "y" nor in "x", nor the root nor anywhere). # Scenario 2 mkfs.btrfs -f /dev/sdc mount /dev/sdc /mnt mkdir /mnt/a echo "hello" > /mnt/a/foo sync mv /mnt/a/foo /mnt/a/bar echo "world" > /mnt/a/foo xfs_io -c fsync /mnt/a/foo <power failure happens> The next time the fs is mounted, log tree replay happens and the file "bar" does not exists anymore. A file with the name "foo" exists and it matches the second file we created. Another related problem that does not involve file/data loss is when a new inode is created with the name of a deleted snapshot and we fsync it: mkfs.btrfs -f /dev/sdc mount /dev/sdc /mnt mkdir /mnt/testdir btrfs subvolume snapshot /mnt /mnt/testdir/snap btrfs subvolume delete /mnt/testdir/snap rmdir /mnt/testdir mkdir /mnt/testdir xfs_io -c fsync /mnt/testdir # or fsync some file inside /mnt/testdir <power failure> The next time the fs is mounted the log replay procedure fails because it attempts to delete the snapshot entry (which has dir item key type of BTRFS_ROOT_ITEM_KEY) as if it were a regular (non-root) entry, resulting in the following error that causes mount to fail: [52174.510532] BTRFS info (device dm-0): failed to delete reference to snap, inode 257 parent 257 [52174.512570] ------------[ cut here ]------------ [52174.513278] WARNING: CPU: 12 PID: 28024 at fs/btrfs/inode.c:3986 __btrfs_unlink_inode+0x178/0x351 [btrfs]() [52174.514681] BTRFS: Transaction aborted (error -2) [52174.515630] Modules linked in: btrfs dm_flakey dm_mod overlay crc32c_generic ppdev xor raid6_pq acpi_cpufreq parport_pc tpm_tis sg parport tpm evdev i2c_piix4 proc [52174.521568] CPU: 12 PID: 28024 Comm: mount Tainted: G W 4.5.0-rc6-btrfs-next-27+ #1 [52174.522805] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS by qemu-project.org 04/01/2014 [52174.524053] 0000000000000000 ffff8801df2a7710 ffffffff81264e93 ffff8801df2a7758 [52174.524053] 0000000000000009 ffff8801df2a7748 ffffffff81051618 ffffffffa03591cd [52174.524053] 00000000fffffffe ffff88015e6e5000 ffff88016dbc3c88 ffff88016dbc3c88 [52174.524053] Call Trace: [52174.524053] [<ffffffff81264e93>] dump_stack+0x67/0x90 [52174.524053] [<ffffffff81051618>] warn_slowpath_common+0x99/0xb2 [52174.524053] [<ffffffffa03591cd>] ? __btrfs_unlink_inode+0x178/0x351 [btrfs] [52174.524053] [<ffffffff81051679>] warn_slowpath_fmt+0x48/0x50 [52174.524053] [<ffffffffa03591cd>] __btrfs_unlink_inode+0x178/0x351 [btrfs] [52174.524053] [<ffffffff8118f5e9>] ? iput+0xb0/0x284 [52174.524053] [<ffffffffa0359fe8>] btrfs_unlink_inode+0x1c/0x3d [btrfs] [52174.524053] [<ffffffffa038631e>] check_item_in_log+0x1fe/0x29b [btrfs] [52174.524053] [<ffffffffa0386522>] replay_dir_deletes+0x167/0x1cf [btrfs] [52174.524053] [<ffffffffa038739e>] fixup_inode_link_count+0x289/0x2aa [btrfs] [52174.524053] [<ffffffffa038748a>] fixup_inode_link_counts+0xcb/0x105 [btrfs] [52174.524053] [<ffffffffa038a5ec>] btrfs_recover_log_trees+0x258/0x32c [btrfs] [52174.524053] [<ffffffffa03885b2>] ? replay_one_extent+0x511/0x511 [btrfs] [52174.524053] [<ffffffffa034f288>] open_ctree+0x1dd4/0x21b9 [btrfs] [52174.524053] [<ffffffffa032b753>] btrfs_mount+0x97e/0xaed [btrfs] [52174.524053] [<ffffffff8108e1b7>] ? trace_hardirqs_on+0xd/0xf [52174.524053] [<ffffffff8117bafa>] mount_fs+0x67/0x131 [52174.524053] [<ffffffff81193003>] vfs_kern_mount+0x6c/0xde [52174.524053] [<ffffffffa032af81>] btrfs_mount+0x1ac/0xaed [btrfs] [52174.524053] [<ffffffff8108e1b7>] ? trace_hardirqs_on+0xd/0xf [52174.524053] [<ffffffff8108c262>] ? lockdep_init_map+0xb9/0x1b3 [52174.524053] [<ffffffff8117bafa>] mount_fs+0x67/0x131 [52174.524053] [<ffffffff81193003>] vfs_kern_mount+0x6c/0xde [52174.524053] [<ffffffff8119590f>] do_mount+0x8a6/0x9e8 [52174.524053] [<ffffffff811358dd>] ? strndup_user+0x3f/0x59 [52174.524053] [<ffffffff81195c65>] SyS_mount+0x77/0x9f [52174.524053] [<ffffffff814935d7>] entry_SYSCALL_64_fastpath+0x12/0x6b [52174.561288] ---[ end trace 6b53049efb1a3ea6 ]--- Fix this by forcing a transaction commit when such cases happen. This means we check in the commit root of the subvolume tree if there was any other inode with the same reference when the inode we are fsync'ing is a new inode (created in the current transaction). Test cases for fstests, covering all the scenarios given above, were submitted upstream for fstests: * fstests: generic test for fsync after renaming directory https://patchwork.kernel.org/patch/8694281/ * fstests: generic test for fsync after renaming file https://patchwork.kernel.org/patch/8694301/ * fstests: add btrfs test for fsync after snapshot deletion https://patchwork.kernel.org/patch/8670671/ Cc: stable@vger.kernel.org Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Chris Mason <clm@fb.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
* Btrfs: fix fsync after truncate when no_holes feature is enabledFilipe Manana2016-04-201-0/+108
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit a89ca6f24ffe435edad57de02eaabd37a2c6bff6 ] When we have the no_holes feature enabled, if a we truncate a file to a smaller size, truncate it again but to a size greater than or equals to its original size and fsync it, the log tree will not have any information about the hole covering the range [truncate_1_offset, new_file_size[. Which means if the fsync log is replayed, the file will remain with the state it had before both truncate operations. Without the no_holes feature this does not happen, since when the inode is logged (full sync flag is set) it will find in the fs/subvol tree a leaf with a generation matching the current transaction id that has an explicit extent item representing the hole. Fix this by adding an explicit extent item representing a hole between the last extent and the inode's i_size if we are doing a full sync. The issue is easy to reproduce with the following test case for fstests: . ./common/rc . ./common/filter . ./common/dmflakey _need_to_be_root _supported_fs generic _supported_os Linux _require_scratch _require_dm_flakey # This test was motivated by an issue found in btrfs when the btrfs # no-holes feature is enabled (introduced in kernel 3.14). So enable # the feature if the fs being tested is btrfs. if [ $FSTYP == "btrfs" ]; then _require_btrfs_fs_feature "no_holes" _require_btrfs_mkfs_feature "no-holes" MKFS_OPTIONS="$MKFS_OPTIONS -O no-holes" fi rm -f $seqres.full _scratch_mkfs >>$seqres.full 2>&1 _init_flakey _mount_flakey # Create our test files and make sure everything is durably persisted. $XFS_IO_PROG -f -c "pwrite -S 0xaa 0 64K" \ -c "pwrite -S 0xbb 64K 61K" \ $SCRATCH_MNT/foo | _filter_xfs_io $XFS_IO_PROG -f -c "pwrite -S 0xee 0 64K" \ -c "pwrite -S 0xff 64K 61K" \ $SCRATCH_MNT/bar | _filter_xfs_io sync # Now truncate our file foo to a smaller size (64Kb) and then truncate # it to the size it had before the shrinking truncate (125Kb). Then # fsync our file. If a power failure happens after the fsync, we expect # our file to have a size of 125Kb, with the first 64Kb of data having # the value 0xaa and the second 61Kb of data having the value 0x00. $XFS_IO_PROG -c "truncate 64K" \ -c "truncate 125K" \ -c "fsync" \ $SCRATCH_MNT/foo # Do something similar to our file bar, but the first truncation sets # the file size to 0 and the second truncation expands the size to the # double of what it was initially. $XFS_IO_PROG -c "truncate 0" \ -c "truncate 253K" \ -c "fsync" \ $SCRATCH_MNT/bar _load_flakey_table $FLAKEY_DROP_WRITES _unmount_flakey # Allow writes again, mount to trigger log replay and validate file # contents. _load_flakey_table $FLAKEY_ALLOW_WRITES _mount_flakey # We expect foo to have a size of 125Kb, the first 64Kb of data all # having the value 0xaa and the remaining 61Kb to be a hole (all bytes # with value 0x00). echo "File foo content after log replay:" od -t x1 $SCRATCH_MNT/foo # We expect bar to have a size of 253Kb and no extents (any byte read # from bar has the value 0x00). echo "File bar content after log replay:" od -t x1 $SCRATCH_MNT/bar status=0 exit The expected file contents in the golden output are: File foo content after log replay: 0000000 aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa * 0200000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 * 0372000 File bar content after log replay: 0000000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 * 0772000 Without this fix, their contents are: File foo content after log replay: 0000000 aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa * 0200000 bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb * 0372000 File bar content after log replay: 0000000 ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee * 0200000 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff * 0372000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 * 0772000 A test case submission for fstests follows soon. Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: Chris Mason <clm@fb.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
* Btrfs: fix fsync xattr loss in the fast fsync pathFilipe Manana2016-04-201-0/+104
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit 36283bf777d963fac099213297e155d071096994 ] After commit 4f764e515361 ("Btrfs: remove deleted xattrs on fsync log replay"), we can end up in a situation where during log replay we end up deleting xattrs that were never deleted when their file was last fsynced. This happens in the fast fsync path (flag BTRFS_INODE_NEEDS_FULL_SYNC is not set in the inode) if the inode has the flag BTRFS_INODE_COPY_EVERYTHING set, the xattr was added in a past transaction and the leaf where the xattr is located was not updated (COWed or created) in the current transaction. In this scenario the xattr item never ends up in the log tree and therefore at log replay time, which makes the replay code delete the xattr from the fs/subvol tree as it thinks that xattr was deleted prior to the last fsync. Fix this by always logging all xattrs, which is the simplest and most reliable way to detect deleted xattrs and replay the deletes at log replay time. This issue is reproducible with the following test case for fstests: seq=`basename $0` seqres=$RESULT_DIR/$seq echo "QA output created by $seq" here=`pwd` tmp=/tmp/$$ status=1 # failure is the default! _cleanup() { _cleanup_flakey rm -f $tmp.* } trap "_cleanup; exit \$status" 0 1 2 3 15 # get standard environment, filters and checks . ./common/rc . ./common/filter . ./common/dmflakey . ./common/attr # real QA test starts here # We create a lot of xattrs for a single file. Only btrfs and xfs are currently # able to store such a large mount of xattrs per file, other filesystems such # as ext3/4 and f2fs for example, fail with ENOSPC even if we attempt to add # less than 1000 xattrs with very small values. _supported_fs btrfs xfs _supported_os Linux _need_to_be_root _require_scratch _require_dm_flakey _require_attrs _require_metadata_journaling $SCRATCH_DEV rm -f $seqres.full _scratch_mkfs >> $seqres.full 2>&1 _init_flakey _mount_flakey # Create the test file with some initial data and make sure everything is # durably persisted. $XFS_IO_PROG -f -c "pwrite -S 0xaa 0 32k" $SCRATCH_MNT/foo | _filter_xfs_io sync # Add many small xattrs to our file. # We create such a large amount because it's needed to trigger the issue found # in btrfs - we need to have an amount that causes the fs to have at least 3 # btree leafs with xattrs stored in them, and it must work on any leaf size # (maximum leaf/node size is 64Kb). num_xattrs=2000 for ((i = 1; i <= $num_xattrs; i++)); do name="user.attr_$(printf "%04d" $i)" $SETFATTR_PROG -n $name -v "val_$(printf "%04d" $i)" $SCRATCH_MNT/foo done # Sync the filesystem to force a commit of the current btrfs transaction, this # is a necessary condition to trigger the bug on btrfs. sync # Now update our file's data and fsync the file. # After a successful fsync, if the fsync log/journal is replayed we expect to # see all the xattrs we added before with the same values (and the updated file # data of course). Btrfs used to delete some of these xattrs when it replayed # its fsync log/journal. $XFS_IO_PROG -c "pwrite -S 0xbb 8K 16K" \ -c "fsync" \ $SCRATCH_MNT/foo | _filter_xfs_io # Simulate a crash/power loss. _load_flakey_table $FLAKEY_DROP_WRITES _unmount_flakey # Allow writes again and mount. This makes the fs replay its fsync log. _load_flakey_table $FLAKEY_ALLOW_WRITES _mount_flakey echo "File content after crash and log replay:" od -t x1 $SCRATCH_MNT/foo echo "File xattrs after crash and log replay:" for ((i = 1; i <= $num_xattrs; i++)); do name="user.attr_$(printf "%04d" $i)" echo -n "$name=" $GETFATTR_PROG --absolute-names -n $name --only-values $SCRATCH_MNT/foo echo done status=0 exit The golden output expects all xattrs to be available, and with the correct values, after the fsync log is replayed. Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Chris Mason <clm@fb.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
* Btrfs: fix fsync data loss after append writeFilipe Manana2016-04-201-5/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit e4545de5b035c7debb73d260c78377dbb69cbfb5 ] If we do an append write to a file (which increases its inode's i_size) that does not have the flag BTRFS_INODE_NEEDS_FULL_SYNC set in its inode, and the previous transaction added a new hard link to the file, which sets the flag BTRFS_INODE_COPY_EVERYTHING in the file's inode, and then fsync the file, the inode's new i_size isn't logged. This has the consequence that after the fsync log is replayed, the file size remains what it was before the append write operation, which means users/applications will not be able to read the data that was successsfully fsync'ed before. This happens because neither the inode item nor the delayed inode get their i_size updated when the append write is made - doing so would require starting a transaction in the buffered write path, something that we do not do intentionally for performance reasons. Fix this by making sure that when the flag BTRFS_INODE_COPY_EVERYTHING is set the inode is logged with its current i_size (log the in-memory inode into the log tree). This issue is not a recent regression and is easy to reproduce with the following test case for fstests: seq=`basename $0` seqres=$RESULT_DIR/$seq echo "QA output created by $seq" here=`pwd` tmp=/tmp/$$ status=1 # failure is the default! _cleanup() { _cleanup_flakey rm -f $tmp.* } trap "_cleanup; exit \$status" 0 1 2 3 15 # get standard environment, filters and checks . ./common/rc . ./common/filter . ./common/dmflakey # real QA test starts here _supported_fs generic _supported_os Linux _need_to_be_root _require_scratch _require_dm_flakey _require_metadata_journaling $SCRATCH_DEV _crash_and_mount() { # Simulate a crash/power loss. _load_flakey_table $FLAKEY_DROP_WRITES _unmount_flakey # Allow writes again and mount. This makes the fs replay its fsync log. _load_flakey_table $FLAKEY_ALLOW_WRITES _mount_flakey } rm -f $seqres.full _scratch_mkfs >> $seqres.full 2>&1 _init_flakey _mount_flakey # Create the test file with some initial data and then fsync it. # The fsync here is only needed to trigger the issue in btrfs, as it causes the # the flag BTRFS_INODE_NEEDS_FULL_SYNC to be removed from the btrfs inode. $XFS_IO_PROG -f -c "pwrite -S 0xaa 0 32k" \ -c "fsync" \ $SCRATCH_MNT/foo | _filter_xfs_io sync # Add a hard link to our file. # On btrfs this sets the flag BTRFS_INODE_COPY_EVERYTHING on the btrfs inode, # which is a necessary condition to trigger the issue. ln $SCRATCH_MNT/foo $SCRATCH_MNT/bar # Sync the filesystem to force a commit of the current btrfs transaction, this # is a necessary condition to trigger the bug on btrfs. sync # Now append more data to our file, increasing its size, and fsync the file. # In btrfs because the inode flag BTRFS_INODE_COPY_EVERYTHING was set and the # write path did not update the inode item in the btree nor the delayed inode # item (in memory struture) in the current transaction (created by the fsync # handler), the fsync did not record the inode's new i_size in the fsync # log/journal. This made the data unavailable after the fsync log/journal is # replayed. $XFS_IO_PROG -c "pwrite -S 0xbb 32K 32K" \ -c "fsync" \ $SCRATCH_MNT/foo | _filter_xfs_io echo "File content after fsync and before crash:" od -t x1 $SCRATCH_MNT/foo _crash_and_mount echo "File content after crash and log replay:" od -t x1 $SCRATCH_MNT/foo status=0 exit The expected file output before and after the crash/power failure expects the appended data to be available, which is: 0000000 aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa * 0100000 bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb * 0200000 Cc: stable@vger.kernel.org Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: Chris Mason <clm@fb.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
* btrfs: async-thread: Fix a use-after-free error for traceQu Wenruo2016-04-131-1/+1
| | | | | | | | | | | | | | | [ Upstream commit 0a95b851370b84a4b9d92ee6d1fa0926901d0454 ] Parameter of trace_btrfs_work_queued() can be freed in its workqueue. So no one use use that pointer after queue_work(). Fix the user-after-free bug by move the trace line before queue_work(). Reported-by: Dave Jones <davej@codemonkey.org.uk> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: Chris Mason <clm@fb.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
* btrfs: initialize the seq counter in struct btrfs_deviceSebastian Andrzej Siewior2016-04-131-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit 546bed631203344611f42b2af1d224d2eedb4e6b ] I managed to trigger this: | INFO: trying to register non-static key. | the code is fine but needs lockdep annotation. | turning off the locking correctness validator. | CPU: 1 PID: 781 Comm: systemd-gpt-aut Not tainted 4.4.0-rt2+ #14 | Hardware name: ARM-Versatile Express | [<80307cec>] (dump_stack) | [<80070e98>] (__lock_acquire) | [<8007184c>] (lock_acquire) | [<80287800>] (btrfs_ioctl) | [<8012a8d4>] (do_vfs_ioctl) | [<8012ac14>] (SyS_ioctl) so I think that btrfs_device_data_ordered_init() is not invoked behind a macro somewhere. Fixes: 7cc8e58d53cd ("Btrfs: fix unprotected device's variants on 32bits machine") Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
* Btrfs: fix transaction handle leak on failure to create hard linkFilipe Manana2016-04-131-2/+4
| | | | | | | | | | | | | | [ Upstream commit 271dba4521aed0c37c063548f876b49f5cd64b2e ] If we failed to create a hard link we were not always releasing the the transaction handle we got before, resulting in a memory leak and preventing any other tasks from being able to commit the current transaction. Fix this by always releasing our transaction handle. Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
* Btrfs: fix number of transaction units required to create symlinkFilipe Manana2016-04-131-1/+3
| | | | | | | | | | | | [ Upstream commit 9269d12b2d57d9e3d13036bb750762d1110d425c ] We weren't accounting for the insertion of an inline extent item for the symlink inode nor that we need to update the parent inode item (through the call to btrfs_add_nondir()). So fix this by including two more transaction units. Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
* Btrfs: send, don't BUG_ON() when an empty symlink is foundFilipe Manana2016-04-131-1/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit a879719b8c90e15c9e7fa7266d5e3c0ca962f9df ] When a symlink is successfully created it always has an inline extent containing the source path. However if an error happens when creating the symlink, we can leave in the subvolume's tree a symlink inode without any such inline extent item - this happens if after btrfs_symlink() calls btrfs_end_transaction() and before it calls the inode eviction handler (through the final iput() call), the transaction gets committed and a crash happens before the eviction handler gets called, or if a snapshot of the subvolume is made before the eviction handler gets called. Sadly we can't just avoid this by making btrfs_symlink() call btrfs_end_transaction() after it calls the eviction handler, because the later can commit the current transaction before it removes any items from the subvolume tree (if it encounters ENOSPC errors while reserving space for removing all the items). So make send fail more gracefully, with an -EIO error, and print a message to dmesg/syslog informing that there's an empty symlink inode, so that the user can delete the empty symlink or do something else about it. Reported-by: Stephen R. van den Berg <srb@cuci.nl> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
* btrfs: statfs: report zero available if metadata are exhaustedDavid Sterba2016-04-131-0/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit ca8a51b3a979d57b082b14eda38602b7f52d81d1 ] There is one ENOSPC case that's very confusing. There's Available greater than zero but no file operation succeds (besides removing files). This happens when the metadata are exhausted and there's no possibility to allocate another chunk. In this scenario it's normal that there's still some space in the data chunk and the calculation in df reflects that in the Avail value. To at least give some clue about the ENOSPC situation, let statfs report zero value in Avail, even if there's still data space available. Current: /dev/sdb1 4.0G 3.3G 719M 83% /mnt/test New: /dev/sdb1 4.0G 3.3G 0 100% /mnt/test We calculate the remaining metadata space minus global reserve. If this is (supposedly) smaller than zero, there's no space. But this does not hold in practice, the exhausted state happens where's still some positive delta. So we apply some guesswork and compare the delta to a 4M threshold. (Practically observed delta was 2M.) We probably cannot calculate the exact threshold value because this depends on the internal reservations requested by various operations, so some operations that consume a few metadata will succeed even if the Avail is zero. But this is better than the other way around. Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
* Btrfs: igrab inode in writepageJosef Bacik2016-04-131-2/+15
| | | | | | | | | | | | | | | | | [ Upstream commit be7bd730841e69fe8f70120098596f648cd1f3ff ] We hit this panic on a few of our boxes this week where we have an ordered_extent with an NULL inode. We do an igrab() of the inode in writepages, but weren't doing it in writepage which can be called directly from the VM on dirty pages. If the inode has been unlinked then we could have I_FREEING set which means igrab() would return NULL and we get this panic. Fix this by trying to igrab in btrfs_writepage, and if it returns NULL then just redirty the page and return AOP_WRITEPAGE_ACTIVATE; so the VM knows it wasn't successful. Thanks, Signed-off-by: Josef Bacik <jbacik@fb.com> Reviewed-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
* Btrfs: add missing brelse when superblock checksum failsAnand Jain2016-04-131-0/+1
| | | | | | | | | | | | | [ Upstream commit b2acdddfad13c38a1e8b927d83c3cf321f63601a ] Looks like oversight, call brelse() when checksum fails. Further down the code, in the non error path, we do call brelse() and so we don't see brelse() in the goto error paths. Signed-off-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
* btrfs: properly set the termination value of ctx->pos in readdirDavid Sterba2016-03-043-3/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit bc4ef7592f657ae81b017207a1098817126ad4cb ] The value of ctx->pos in the last readdir call is supposed to be set to INT_MAX due to 32bit compatibility, unless 'pos' is intentially set to a larger value, then it's LLONG_MAX. There's a report from PaX SIZE_OVERFLOW plugin that "ctx->pos++" overflows (https://forums.grsecurity.net/viewtopic.php?f=1&t=4284), on a 64bit arch, where the value is 0x7fffffffffffffff ie. LLONG_MAX before the increment. We can get to that situation like that: * emit all regular readdir entries * still in the same call to readdir, bump the last pos to INT_MAX * next call to readdir will not emit any entries, but will reach the bump code again, finds pos to be INT_MAX and sets it to LLONG_MAX Normally this is not a problem, but if we call readdir again, we'll find 'pos' set to LLONG_MAX and the unconditional increment will overflow. The report from Victor at (http://thread.gmane.org/gmane.comp.file-systems.btrfs/49500) with debugging print shows that pattern: Overflow: e Overflow: 7fffffff Overflow: 7fffffffffffffff PAX: size overflow detected in function btrfs_real_readdir fs/btrfs/inode.c:5760 cicus.935_282 max, count: 9, decl: pos; num: 0; context: dir_context; CPU: 0 PID: 2630 Comm: polkitd Not tainted 4.2.3-grsec #1 Hardware name: Gigabyte Technology Co., Ltd. H81ND2H/H81ND2H, BIOS F3 08/11/2015 ffffffff81901608 0000000000000000 ffffffff819015e6 ffffc90004973d48 ffffffff81742f0f 0000000000000007 ffffffff81901608 ffffc90004973d78 ffffffff811cb706 0000000000000000 ffff8800d47359e0 ffffc90004973ed8 Call Trace: [<ffffffff81742f0f>] dump_stack+0x4c/0x7f [<ffffffff811cb706>] report_size_overflow+0x36/0x40 [<ffffffff812ef0bc>] btrfs_real_readdir+0x69c/0x6d0 [<ffffffff811dafc8>] iterate_dir+0xa8/0x150 [<ffffffff811e6d8d>] ? __fget_light+0x2d/0x70 [<ffffffff811dba3a>] SyS_getdents+0xba/0x1c0 Overflow: 1a [<ffffffff811db070>] ? iterate_dir+0x150/0x150 [<ffffffff81749b69>] entry_SYSCALL_64_fastpath+0x12/0x83 The jump from 7fffffff to 7fffffffffffffff happens when new dir entries are not yet synced and are processed from the delayed list. Then the code could go to the bump section again even though it might not emit any new dir entries from the delayed list. The fix avoids entering the "bump" section again once we've finished emitting the entries, both for synced and delayed entries. References: https://forums.grsecurity.net/viewtopic.php?f=1&t=4284 Reported-by: Victor <services@swwu.com> CC: stable@vger.kernel.org Signed-off-by: David Sterba <dsterba@suse.com> Tested-by: Holger Hoffstätte <holger.hoffstaette@googlemail.com> Signed-off-by: Chris Mason <clm@fb.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
* Btrfs: fix hang on extent buffer lock caused by the inode_paths ioctlFilipe Manana2016-03-021-4/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit 0c0fe3b0fa45082cd752553fdb3a4b42503a118e ] While doing some tests I ran into an hang on an extent buffer's rwlock that produced the following trace: [39389.800012] NMI watchdog: BUG: soft lockup - CPU#15 stuck for 22s! [fdm-stress:32166] [39389.800016] NMI watchdog: BUG: soft lockup - CPU#14 stuck for 22s! [fdm-stress:32165] [39389.800016] Modules linked in: btrfs dm_mod ppdev xor sha256_generic hmac raid6_pq drbg ansi_cprng aesni_intel i2c_piix4 acpi_cpufreq aes_x86_64 ablk_helper tpm_tis parport_pc i2c_core sg cryptd evdev psmouse lrw tpm parport gf128mul serio_raw pcspkr glue_helper processor button loop autofs4 ext4 crc16 mbcache jbd2 sd_mod sr_mod cdrom ata_generic virtio_scsi ata_piix libata virtio_pci virtio_ring crc32c_intel scsi_mod e1000 virtio floppy [last unloaded: btrfs] [39389.800016] irq event stamp: 0 [39389.800016] hardirqs last enabled at (0): [< (null)>] (null) [39389.800016] hardirqs last disabled at (0): [<ffffffff8104e58d>] copy_process+0x638/0x1a35 [39389.800016] softirqs last enabled at (0): [<ffffffff8104e58d>] copy_process+0x638/0x1a35 [39389.800016] softirqs last disabled at (0): [< (null)>] (null) [39389.800016] CPU: 14 PID: 32165 Comm: fdm-stress Not tainted 4.4.0-rc6-btrfs-next-18+ #1 [39389.800016] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS by qemu-project.org 04/01/2014 [39389.800016] task: ffff880175b1ca40 ti: ffff8800a185c000 task.ti: ffff8800a185c000 [39389.800016] RIP: 0010:[<ffffffff810902af>] [<ffffffff810902af>] queued_spin_lock_slowpath+0x57/0x158 [39389.800016] RSP: 0018:ffff8800a185fb80 EFLAGS: 00000202 [39389.800016] RAX: 0000000000000101 RBX: ffff8801710c4e9c RCX: 0000000000000101 [39389.800016] RDX: 0000000000000100 RSI: 0000000000000001 RDI: 0000000000000001 [39389.800016] RBP: ffff8800a185fb98 R08: 0000000000000001 R09: 0000000000000000 [39389.800016] R10: ffff8800a185fb68 R11: 6db6db6db6db6db7 R12: ffff8801710c4e98 [39389.800016] R13: ffff880175b1ca40 R14: ffff8800a185fc10 R15: ffff880175b1ca40 [39389.800016] FS: 00007f6d37fff700(0000) GS:ffff8802be9c0000(0000) knlGS:0000000000000000 [39389.800016] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [39389.800016] CR2: 00007f6d300019b8 CR3: 0000000037c93000 CR4: 00000000001406e0 [39389.800016] Stack: [39389.800016] ffff8801710c4e98 ffff8801710c4e98 ffff880175b1ca40 ffff8800a185fbb0 [39389.800016] ffffffff81091e11 ffff8801710c4e98 ffff8800a185fbc8 ffffffff81091895 [39389.800016] ffff8801710c4e98 ffff8800a185fbe8 ffffffff81486c5c ffffffffa067288c [39389.800016] Call Trace: [39389.800016] [<ffffffff81091e11>] queued_read_lock_slowpath+0x46/0x60 [39389.800016] [<ffffffff81091895>] do_raw_read_lock+0x3e/0x41 [39389.800016] [<ffffffff81486c5c>] _raw_read_lock+0x3d/0x44 [39389.800016] [<ffffffffa067288c>] ? btrfs_tree_read_lock+0x54/0x125 [btrfs] [39389.800016] [<ffffffffa067288c>] btrfs_tree_read_lock+0x54/0x125 [btrfs] [39389.800016] [<ffffffffa0622ced>] ? btrfs_find_item+0xa7/0xd2 [btrfs] [39389.800016] [<ffffffffa069363f>] btrfs_ref_to_path+0xd6/0x174 [btrfs] [39389.800016] [<ffffffffa0693730>] inode_to_path+0x53/0xa2 [btrfs] [39389.800016] [<ffffffffa0693e2e>] paths_from_inode+0x117/0x2ec [btrfs] [39389.800016] [<ffffffffa0670cff>] btrfs_ioctl+0xd5b/0x2793 [btrfs] [39389.800016] [<ffffffff8108a8b0>] ? arch_local_irq_save+0x9/0xc [39389.800016] [<ffffffff81276727>] ? __this_cpu_preempt_check+0x13/0x15 [39389.800016] [<ffffffff8108a8b0>] ? arch_local_irq_save+0x9/0xc [39389.800016] [<ffffffff8118b3d4>] ? rcu_read_unlock+0x3e/0x5d [39389.800016] [<ffffffff811822f8>] do_vfs_ioctl+0x42b/0x4ea [39389.800016] [<ffffffff8118b4f3>] ? __fget_light+0x62/0x71 [39389.800016] [<ffffffff8118240e>] SyS_ioctl+0x57/0x79 [39389.800016] [<ffffffff814872d7>] entry_SYSCALL_64_fastpath+0x12/0x6f [39389.800016] Code: b9 01 01 00 00 f7 c6 00 ff ff ff 75 32 83 fe 01 89 ca 89 f0 0f 45 d7 f0 0f b1 13 39 f0 74 04 89 c6 eb e2 ff ca 0f 84 fa 00 00 00 <8b> 03 84 c0 74 04 f3 90 eb f6 66 c7 03 01 00 e9 e6 00 00 00 e8 [39389.800012] Modules linked in: btrfs dm_mod ppdev xor sha256_generic hmac raid6_pq drbg ansi_cprng aesni_intel i2c_piix4 acpi_cpufreq aes_x86_64 ablk_helper tpm_tis parport_pc i2c_core sg cryptd evdev psmouse lrw tpm parport gf128mul serio_raw pcspkr glue_helper processor button loop autofs4 ext4 crc16 mbcache jbd2 sd_mod sr_mod cdrom ata_generic virtio_scsi ata_piix libata virtio_pci virtio_ring crc32c_intel scsi_mod e1000 virtio floppy [last unloaded: btrfs] [39389.800012] irq event stamp: 0 [39389.800012] hardirqs last enabled at (0): [< (null)>] (null) [39389.800012] hardirqs last disabled at (0): [<ffffffff8104e58d>] copy_process+0x638/0x1a35 [39389.800012] softirqs last enabled at (0): [<ffffffff8104e58d>] copy_process+0x638/0x1a35 [39389.800012] softirqs last disabled at (0): [< (null)>] (null) [39389.800012] CPU: 15 PID: 32166 Comm: fdm-stress Tainted: G L 4.4.0-rc6-btrfs-next-18+ #1 [39389.800012] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS by qemu-project.org 04/01/2014 [39389.800012] task: ffff880179294380 ti: ffff880034a60000 task.ti: ffff880034a60000 [39389.800012] RIP: 0010:[<ffffffff81091e8d>] [<ffffffff81091e8d>] queued_write_lock_slowpath+0x62/0x72 [39389.800012] RSP: 0018:ffff880034a639f0 EFLAGS: 00000206 [39389.800012] RAX: 0000000000000101 RBX: ffff8801710c4e98 RCX: 0000000000000000 [39389.800012] RDX: 00000000000000ff RSI: 0000000000000000 RDI: ffff8801710c4e9c [39389.800012] RBP: ffff880034a639f8 R08: 0000000000000001 R09: 0000000000000000 [39389.800012] R10: ffff880034a639b0 R11: 0000000000001000 R12: ffff8801710c4e98 [39389.800012] R13: 0000000000000001 R14: ffff880172cbc000 R15: ffff8801710c4e00 [39389.800012] FS: 00007f6d377fe700(0000) GS:ffff8802be9e0000(0000) knlGS:0000000000000000 [39389.800012] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [39389.800012] CR2: 00007f6d3d3c1000 CR3: 0000000037c93000 CR4: 00000000001406e0 [39389.800012] Stack: [39389.800012] ffff8801710c4e98 ffff880034a63a10 ffffffff81091963 ffff8801710c4e98 [39389.800012] ffff880034a63a30 ffffffff81486f1b ffffffffa0672cb3 ffff8801710c4e00 [39389.800012] ffff880034a63a78 ffffffffa0672cb3 ffff8801710c4e00 ffff880034a63a58 [39389.800012] Call Trace: [39389.800012] [<ffffffff81091963>] do_raw_write_lock+0x72/0x8c [39389.800012] [<ffffffff81486f1b>] _raw_write_lock+0x3a/0x41 [39389.800012] [<ffffffffa0672cb3>] ? btrfs_tree_lock+0x119/0x251 [btrfs] [39389.800012] [<ffffffffa0672cb3>] btrfs_tree_lock+0x119/0x251 [btrfs] [39389.800012] [<ffffffffa061aeba>] ? rcu_read_unlock+0x5b/0x5d [btrfs] [39389.800012] [<ffffffffa061ce13>] ? btrfs_root_node+0xda/0xe6 [btrfs] [39389.800012] [<ffffffffa061ce83>] btrfs_lock_root_node+0x22/0x42 [btrfs] [39389.800012] [<ffffffffa062046b>] btrfs_search_slot+0x1b8/0x758 [btrfs] [39389.800012] [<ffffffff810fc6b0>] ? time_hardirqs_on+0x15/0x28 [39389.800012] [<ffffffffa06365db>] btrfs_lookup_inode+0x31/0x95 [btrfs] [39389.800012] [<ffffffff8108d62f>] ? trace_hardirqs_on+0xd/0xf [39389.800012] [<ffffffff8148482b>] ? mutex_lock_nested+0x397/0x3bc [39389.800012] [<ffffffffa068821b>] __btrfs_update_delayed_inode+0x59/0x1c0 [btrfs] [39389.800012] [<ffffffffa068858e>] __btrfs_commit_inode_delayed_items+0x194/0x5aa [btrfs] [39389.800012] [<ffffffff81486ab7>] ? _raw_spin_unlock+0x31/0x44 [39389.800012] [<ffffffffa0688a48>] __btrfs_run_delayed_items+0xa4/0x15c [btrfs] [39389.800012] [<ffffffffa0688d62>] btrfs_run_delayed_items+0x11/0x13 [btrfs] [39389.800012] [<ffffffffa064048e>] btrfs_commit_transaction+0x234/0x96e [btrfs] [39389.800012] [<ffffffffa0618d10>] btrfs_sync_fs+0x145/0x1ad [btrfs] [39389.800012] [<ffffffffa0671176>] btrfs_ioctl+0x11d2/0x2793 [btrfs] [39389.800012] [<ffffffff8108a8b0>] ? arch_local_irq_save+0x9/0xc [39389.800012] [<ffffffff81140261>] ? __might_fault+0x4c/0xa7 [39389.800012] [<ffffffff81140261>] ? __might_fault+0x4c/0xa7 [39389.800012] [<ffffffff8108a8b0>] ? arch_local_irq_save+0x9/0xc [39389.800012] [<ffffffff8118b3d4>] ? rcu_read_unlock+0x3e/0x5d [39389.800012] [<ffffffff811822f8>] do_vfs_ioctl+0x42b/0x4ea [39389.800012] [<ffffffff8118b4f3>] ? __fget_light+0x62/0x71 [39389.800012] [<ffffffff8118240e>] SyS_ioctl+0x57/0x79 [39389.800012] [<ffffffff814872d7>] entry_SYSCALL_64_fastpath+0x12/0x6f [39389.800012] Code: f0 0f b1 13 85 c0 75 ef eb 2a f3 90 8a 03 84 c0 75 f8 f0 0f b0 13 84 c0 75 f0 ba ff 00 00 00 eb 0a f0 0f b1 13 ff c8 74 0b f3 90 <8b> 03 83 f8 01 75 f7 eb ed c6 43 04 00 5b 5d c3 0f 1f 44 00 00 This happens because in the code path executed by the inode_paths ioctl we end up nesting two calls to read lock a leaf's rwlock when after the first call to read_lock() and before the second call to read_lock(), another task (running the delayed items as part of a transaction commit) has already called write_lock() against the leaf's rwlock. This situation is illustrated by the following diagram: Task A Task B btrfs_ref_to_path() btrfs_commit_transaction() read_lock(&eb->lock); btrfs_run_delayed_items() __btrfs_commit_inode_delayed_items() __btrfs_update_delayed_inode() btrfs_lookup_inode() write_lock(&eb->lock); --> task waits for lock read_lock(&eb->lock); --> makes this task hang forever (and task B too of course) So fix this by avoiding doing the nested read lock, which is easily avoidable. This issue does not happen if task B calls write_lock() after task A does the second call to read_lock(), however there does not seem to exist anything in the documentation that mentions what is the expected behaviour for recursive locking of rwlocks (leaving the idea that doing so is not a good usage of rwlocks). Also, as a side effect necessary for this fix, make sure we do not needlessly read lock extent buffers when the input path has skip_locking set (used when called from send). Cc: stable@vger.kernel.org Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
* Btrfs: fix race when listing an inode's xattrsFilipe Manana2016-01-211-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit f1cd1f0b7d1b5d4aaa5711e8f4e4898b0045cb6d ] When listing a inode's xattrs we have a time window where we race against a concurrent operation for adding a new hard link for our inode that makes us not return any xattr to user space. In order for this to happen, the first xattr of our inode needs to be at slot 0 of a leaf and the previous leaf must still have room for an inode ref (or extref) item, and this can happen because an inode's listxattrs callback does not lock the inode's i_mutex (nor does the VFS does it for us), but adding a hard link to an inode makes the VFS lock the inode's i_mutex before calling the inode's link callback. If we have the following leafs: Leaf X (has N items) Leaf Y [ ... (257 INODE_ITEM 0) (257 INODE_REF 256) ] [ (257 XATTR_ITEM 12345), ... ] slot N - 2 slot N - 1 slot 0 The race illustrated by the following sequence diagram is possible: CPU 1 CPU 2 btrfs_listxattr() searches for key (257 XATTR_ITEM 0) gets path with path->nodes[0] == leaf X and path->slots[0] == N because path->slots[0] is >= btrfs_header_nritems(leaf X), it calls btrfs_next_leaf() btrfs_next_leaf() releases the path adds key (257 INODE_REF 666) to the end of leaf X (slot N), and leaf X now has N + 1 items searches for the key (257 INODE_REF 256), with path->keep_locks == 1, because that is the last key it saw in leaf X before releasing the path ends up at leaf X again and it verifies that the key (257 INODE_REF 256) is no longer the last key in leaf X, so it returns with path->nodes[0] == leaf X and path->slots[0] == N, pointing to the new item with key (257 INODE_REF 666) btrfs_listxattr's loop iteration sees that the type of the key pointed by the path is different from the type BTRFS_XATTR_ITEM_KEY and so it breaks the loop and stops looking for more xattr items --> the application doesn't get any xattr listed for our inode So fix this by breaking the loop only if the key's type is greater than BTRFS_XATTR_ITEM_KEY and skip the current key if its type is smaller. Cc: stable@vger.kernel.org Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
* Btrfs: fix race leading to BUG_ON when running delalloc for nodatacowFilipe Manana2016-01-211-2/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit 1d512cb77bdbda80f0dd0620a3b260d697fd581d ] If we are using the NO_HOLES feature, we have a tiny time window when running delalloc for a nodatacow inode where we can race with a concurrent link or xattr add operation leading to a BUG_ON. This happens because at run_delalloc_nocow() we end up casting a leaf item of type BTRFS_INODE_[REF|EXTREF]_KEY or of type BTRFS_XATTR_ITEM_KEY to a file extent item (struct btrfs_file_extent_item) and then analyse its extent type field, which won't match any of the expected extent types (values BTRFS_FILE_EXTENT_[REG|PREALLOC|INLINE]) and therefore trigger an explicit BUG_ON(1). The following sequence diagram shows how the race happens when running a no-cow dellaloc range [4K, 8K[ for inode 257 and we have the following neighbour leafs: Leaf X (has N items) Leaf Y [ ... (257 INODE_ITEM 0) (257 INODE_REF 256) ] [ (257 EXTENT_DATA 8192), ... ] slot N - 2 slot N - 1 slot 0 (Note the implicit hole for inode 257 regarding the [0, 8K[ range) CPU 1 CPU 2 run_dealloc_nocow() btrfs_lookup_file_extent() --> searches for a key with value (257 EXTENT_DATA 4096) in the fs/subvol tree --> returns us a path with path->nodes[0] == leaf X and path->slots[0] == N because path->slots[0] is >= btrfs_header_nritems(leaf X), it calls btrfs_next_leaf() btrfs_next_leaf() --> releases the path hard link added to our inode, with key (257 INODE_REF 500) added to the end of leaf X, so leaf X now has N + 1 keys --> searches for the key (257 INODE_REF 256), because it was the last key in leaf X before it released the path, with path->keep_locks set to 1 --> ends up at leaf X again and it verifies that the key (257 INODE_REF 256) is no longer the last key in the leaf, so it returns with path->nodes[0] == leaf X and path->slots[0] == N, pointing to the new item with key (257 INODE_REF 500) the loop iteration of run_dealloc_nocow() does not break out the loop and continues because the key referenced in the path at path->nodes[0] and path->slots[0] is for inode 257, its type is < BTRFS_EXTENT_DATA_KEY and its offset (500) is less then our delalloc range's end (8192) the item pointed by the path, an inode reference item, is (incorrectly) interpreted as a file extent item and we get an invalid extent type, leading to the BUG_ON(1): if (extent_type == BTRFS_FILE_EXTENT_REG || extent_type == BTRFS_FILE_EXTENT_PREALLOC) { (...) } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) { (...) } else { BUG_ON(1) } The same can happen if a xattr is added concurrently and ends up having a key with an offset smaller then the delalloc's range end. So fix this by skipping keys with a type smaller than BTRFS_EXTENT_DATA_KEY. Cc: stable@vger.kernel.org Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
* Btrfs: fix race leading to incorrect item deletion when dropping extentsFilipe Manana2016-01-211-4/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit aeafbf8486c9e2bd53f5cc3c10c0b7fd7149d69c ] While running a stress test I got the following warning triggered: [191627.672810] ------------[ cut here ]------------ [191627.673949] WARNING: CPU: 8 PID: 8447 at fs/btrfs/file.c:779 __btrfs_drop_extents+0x391/0xa50 [btrfs]() (...) [191627.701485] Call Trace: [191627.702037] [<ffffffff8145f077>] dump_stack+0x4f/0x7b [191627.702992] [<ffffffff81095de5>] ? console_unlock+0x356/0x3a2 [191627.704091] [<ffffffff8104b3b0>] warn_slowpath_common+0xa1/0xbb [191627.705380] [<ffffffffa0664499>] ? __btrfs_drop_extents+0x391/0xa50 [btrfs] [191627.706637] [<ffffffff8104b46d>] warn_slowpath_null+0x1a/0x1c [191627.707789] [<ffffffffa0664499>] __btrfs_drop_extents+0x391/0xa50 [btrfs] [191627.709155] [<ffffffff8115663c>] ? cache_alloc_debugcheck_after.isra.32+0x171/0x1d0 [191627.712444] [<ffffffff81155007>] ? kmemleak_alloc_recursive.constprop.40+0x16/0x18 [191627.714162] [<ffffffffa06570c9>] insert_reserved_file_extent.constprop.40+0x83/0x24e [btrfs] [191627.715887] [<ffffffffa065422b>] ? start_transaction+0x3bb/0x610 [btrfs] [191627.717287] [<ffffffffa065b604>] btrfs_finish_ordered_io+0x273/0x4e2 [btrfs] [191627.728865] [<ffffffffa065b888>] finish_ordered_fn+0x15/0x17 [btrfs] [191627.730045] [<ffffffffa067d688>] normal_work_helper+0x14c/0x32c [btrfs] [191627.731256] [<ffffffffa067d96a>] btrfs_endio_write_helper+0x12/0x14 [btrfs] [191627.732661] [<ffffffff81061119>] process_one_work+0x24c/0x4ae [191627.733822] [<ffffffff810615b0>] worker_thread+0x206/0x2c2 [191627.734857] [<ffffffff810613aa>] ? process_scheduled_works+0x2f/0x2f [191627.736052] [<ffffffff810613aa>] ? process_scheduled_works+0x2f/0x2f [191627.737349] [<ffffffff810669a6>] kthread+0xef/0xf7 [191627.738267] [<ffffffff810f3b3a>] ? time_hardirqs_on+0x15/0x28 [191627.739330] [<ffffffff810668b7>] ? __kthread_parkme+0xad/0xad [191627.741976] [<ffffffff81465592>] ret_from_fork+0x42/0x70 [191627.743080] [<ffffffff810668b7>] ? __kthread_parkme+0xad/0xad [191627.744206] ---[ end trace bbfddacb7aaada8d ]--- $ cat -n fs/btrfs/file.c 691 int __btrfs_drop_extents(struct btrfs_trans_handle *trans, (...) 758 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); 759 if (key.objectid > ino || 760 key.type > BTRFS_EXTENT_DATA_KEY || key.offset >= end) 761 break; 762 763 fi = btrfs_item_ptr(leaf, path->slots[0], 764 struct btrfs_file_extent_item); 765 extent_type = btrfs_file_extent_type(leaf, fi); 766 767 if (extent_type == BTRFS_FILE_EXTENT_REG || 768 extent_type == BTRFS_FILE_EXTENT_PREALLOC) { (...) 774 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) { (...) 778 } else { 779 WARN_ON(1); 780 extent_end = search_start; 781 } (...) This happened because the item we were processing did not match a file extent item (its key type != BTRFS_EXTENT_DATA_KEY), and even on this case we cast the item to a struct btrfs_file_extent_item pointer and then find a type field value that does not match any of the expected values (BTRFS_FILE_EXTENT_[REG|PREALLOC|INLINE]). This scenario happens due to a tiny time window where a race can happen as exemplified below. For example, consider the following scenario where we're using the NO_HOLES feature and we have the following two neighbour leafs: Leaf X (has N items) Leaf Y [ ... (257 INODE_ITEM 0) (257 INODE_REF 256) ] [ (257 EXTENT_DATA 8192), ... ] slot N - 2 slot N - 1 slot 0 Our inode 257 has an implicit hole in the range [0, 8K[ (implicit rather than explicit because NO_HOLES is enabled). Now if our inode has an ordered extent for the range [4K, 8K[ that is finishing, the following can happen: CPU 1 CPU 2 btrfs_finish_ordered_io() insert_reserved_file_extent() __btrfs_drop_extents() Searches for the key (257 EXTENT_DATA 4096) through btrfs_lookup_file_extent() Key not found and we get a path where path->nodes[0] == leaf X and path->slots[0] == N Because path->slots[0] is >= btrfs_header_nritems(leaf X), we call btrfs_next_leaf() btrfs_next_leaf() releases the path inserts key (257 INODE_REF 4096) at the end of leaf X, leaf X now has N + 1 keys, and the new key is at slot N btrfs_next_leaf() searches for key (257 INODE_REF 256), with path->keep_locks set to 1, because it was the last key it saw in leaf X finds it in leaf X again and notices it's no longer the last key of the leaf, so it returns 0 with path->nodes[0] == leaf X and path->slots[0] == N (which is now < btrfs_header_nritems(leaf X)), pointing to the new key (257 INODE_REF 4096) __btrfs_drop_extents() casts the item at path->nodes[0], slot path->slots[0], to a struct btrfs_file_extent_item - it does not skip keys for the target inode with a type less than BTRFS_EXTENT_DATA_KEY (BTRFS_INODE_REF_KEY < BTRFS_EXTENT_DATA_KEY) sees a bogus value for the type field triggering the WARN_ON in the trace shown above, and sets extent_end = search_start (4096) does the if-then-else logic to fixup 0 length extent items created by a past bug from hole punching: if (extent_end == key.offset && extent_end >= search_start) goto delete_extent_item; that evaluates to true and it ends up deleting the key pointed to by path->slots[0], (257 INODE_REF 4096), from leaf X The same could happen for example for a xattr that ends up having a key with an offset value that matches search_start (very unlikely but not impossible). So fix this by ensuring that keys smaller than BTRFS_EXTENT_DATA_KEY are skipped, never casted to struct btrfs_file_extent_item and never deleted by accident. Also protect against the unexpected case of getting a key for a lower inode number by skipping that key and issuing a warning. Cc: stable@vger.kernel.org Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
* Btrfs: fix file corruption and data loss after cloning inline extentsFilipe Manana2016-01-211-29/+152
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit 8039d87d9e473aeb740d4fdbd59b9d2f89b2ced9 ] Currently the clone ioctl allows to clone an inline extent from one file to another that already has other (non-inlined) extents. This is a problem because btrfs is not designed to deal with files having inline and regular extents, if a file has an inline extent then it must be the only extent in the file and must start at file offset 0. Having a file with an inline extent followed by regular extents results in EIO errors when doing reads or writes against the first 4K of the file. Also, the clone ioctl allows one to lose data if the source file consists of a single inline extent, with a size of N bytes, and the destination file consists of a single inline extent with a size of M bytes, where we have M > N. In this case the clone operation removes the inline extent from the destination file and then copies the inline extent from the source file into the destination file - we lose the M - N bytes from the destination file, a read operation will get the value 0x00 for any bytes in the the range [N, M] (the destination inode's i_size remained as M, that's why we can read past N bytes). So fix this by not allowing such destructive operations to happen and return errno EOPNOTSUPP to user space. Currently the fstest btrfs/035 tests the data loss case but it totally ignores this - i.e. expects the operation to succeed and does not check the we got data loss. The following test case for fstests exercises all these cases that result in file corruption and data loss: seq=`basename $0` seqres=$RESULT_DIR/$seq echo "QA output created by $seq" tmp=/tmp/$$ status=1 # failure is the default! trap "_cleanup; exit \$status" 0 1 2 3 15 _cleanup() { rm -f $tmp.* } # get standard environment, filters and checks . ./common/rc . ./common/filter # real QA test starts here _need_to_be_root _supported_fs btrfs _supported_os Linux _require_scratch _require_cloner _require_btrfs_fs_feature "no_holes" _require_btrfs_mkfs_feature "no-holes" rm -f $seqres.full test_cloning_inline_extents() { local mkfs_opts=$1 local mount_opts=$2 _scratch_mkfs $mkfs_opts >>$seqres.full 2>&1 _scratch_mount $mount_opts # File bar, the source for all the following clone operations, consists # of a single inline extent (50 bytes). $XFS_IO_PROG -f -c "pwrite -S 0xbb 0 50" $SCRATCH_MNT/bar \ | _filter_xfs_io # Test cloning into a file with an extent (non-inlined) where the # destination offset overlaps that extent. It should not be possible to # clone the inline extent from file bar into this file. $XFS_IO_PROG -f -c "pwrite -S 0xaa 0K 16K" $SCRATCH_MNT/foo \ | _filter_xfs_io $CLONER_PROG -s 0 -d 0 -l 0 $SCRATCH_MNT/bar $SCRATCH_MNT/foo # Doing IO against any range in the first 4K of the file should work. # Due to a past clone ioctl bug which allowed cloning the inline extent, # these operations resulted in EIO errors. echo "File foo data after clone operation:" # All bytes should have the value 0xaa (clone operation failed and did # not modify our file). od -t x1 $SCRATCH_MNT/foo $XFS_IO_PROG -c "pwrite -S 0xcc 0 100" $SCRATCH_MNT/foo | _filter_xfs_io # Test cloning the inline extent against a file which has a hole in its # first 4K followed by a non-inlined extent. It should not be possible # as well to clone the inline extent from file bar into this file. $XFS_IO_PROG -f -c "pwrite -S 0xdd 4K 12K" $SCRATCH_MNT/foo2 \ | _filter_xfs_io $CLONER_PROG -s 0 -d 0 -l 0 $SCRATCH_MNT/bar $SCRATCH_MNT/foo2 # Doing IO against any range in the first 4K of the file should work. # Due to a past clone ioctl bug which allowed cloning the inline extent, # these operations resulted in EIO errors. echo "File foo2 data after clone operation:" # All bytes should have the value 0x00 (clone operation failed and did # not modify our file). od -t x1 $SCRATCH_MNT/foo2 $XFS_IO_PROG -c "pwrite -S 0xee 0 90" $SCRATCH_MNT/foo2 | _filter_xfs_io # Test cloning the inline extent against a file which has a size of zero # but has a prealloc extent. It should not be possible as well to clone # the inline extent from file bar into this file. $XFS_IO_PROG -f -c "falloc -k 0 1M" $SCRATCH_MNT/foo3 | _filter_xfs_io $CLONER_PROG -s 0 -d 0 -l 0 $SCRATCH_MNT/bar $SCRATCH_MNT/foo3 # Doing IO against any range in the first 4K of the file should work. # Due to a past clone ioctl bug which allowed cloning the inline extent, # these operations resulted in EIO errors. echo "First 50 bytes of foo3 after clone operation:" # Should not be able to read any bytes, file has 0 bytes i_size (the # clone operation failed and did not modify our file). od -t x1 $SCRATCH_MNT/foo3 $XFS_IO_PROG -c "pwrite -S 0xff 0 90" $SCRATCH_MNT/foo3 | _filter_xfs_io # Test cloning the inline extent against a file which consists of a # single inline extent that has a size not greater than the size of # bar's inline extent (40 < 50). # It should be possible to do the extent cloning from bar to this file. $XFS_IO_PROG -f -c "pwrite -S 0x01 0 40" $SCRATCH_MNT/foo4 \ | _filter_xfs_io $CLONER_PROG -s 0 -d 0 -l 0 $SCRATCH_MNT/bar $SCRATCH_MNT/foo4 # Doing IO against any range in the first 4K of the file should work. echo "File foo4 data after clone operation:" # Must match file bar's content. od -t x1 $SCRATCH_MNT/foo4 $XFS_IO_PROG -c "pwrite -S 0x02 0 90" $SCRATCH_MNT/foo4 | _filter_xfs_io # Test cloning the inline extent against a file which consists of a # single inline extent that has a size greater than the size of bar's # inline extent (60 > 50). # It should not be possible to clone the inline extent from file bar # into this file. $XFS_IO_PROG -f -c "pwrite -S 0x03 0 60" $SCRATCH_MNT/foo5 \ | _filter_xfs_io $CLONER_PROG -s 0 -d 0 -l 0 $SCRATCH_MNT/bar $SCRATCH_MNT/foo5 # Reading the file should not fail. echo "File foo5 data after clone operation:" # Must have a size of 60 bytes, with all bytes having a value of 0x03 # (the clone operation failed and did not modify our file). od -t x1 $SCRATCH_MNT/foo5 # Test cloning the inline extent against a file which has no extents but # has a size greater than bar's inline extent (16K > 50). # It should not be possible to clone the inline extent from file bar # into this file. $XFS_IO_PROG -f -c "truncate 16K" $SCRATCH_MNT/foo6 | _filter_xfs_io $CLONER_PROG -s 0 -d 0 -l 0 $SCRATCH_MNT/bar $SCRATCH_MNT/foo6 # Reading the file should not fail. echo "File foo6 data after clone operation:" # Must have a size of 16K, with all bytes having a value of 0x00 (the # clone operation failed and did not modify our file). od -t x1 $SCRATCH_MNT/foo6 # Test cloning the inline extent against a file which has no extents but # has a size not greater than bar's inline extent (30 < 50). # It should be possible to clone the inline extent from file bar into # this file. $XFS_IO_PROG -f -c "truncate 30" $SCRATCH_MNT/foo7 | _filter_xfs_io $CLONER_PROG -s 0 -d 0 -l 0 $SCRATCH_MNT/bar $SCRATCH_MNT/foo7 # Reading the file should not fail. echo "File foo7 data after clone operation:" # Must have a size of 50 bytes, with all bytes having a value of 0xbb. od -t x1 $SCRATCH_MNT/foo7 # Test cloning the inline extent against a file which has a size not # greater than the size of bar's inline extent (20 < 50) but has # a prealloc extent that goes beyond the file's size. It should not be # possible to clone the inline extent from bar into this file. $XFS_IO_PROG -f -c "falloc -k 0 1M" \ -c "pwrite -S 0x88 0 20" \ $SCRATCH_MNT/foo8 | _filter_xfs_io $CLONER_PROG -s 0 -d 0 -l 0 $SCRATCH_MNT/bar $SCRATCH_MNT/foo8 echo "File foo8 data after clone operation:" # Must have a size of 20 bytes, with all bytes having a value of 0x88 # (the clone operation did not modify our file). od -t x1 $SCRATCH_MNT/foo8 _scratch_unmount } echo -e "\nTesting without compression and without the no-holes feature...\n" test_cloning_inline_extents echo -e "\nTesting with compression and without the no-holes feature...\n" test_cloning_inline_extents "" "-o compress" echo -e "\nTesting without compression and with the no-holes feature...\n" test_cloning_inline_extents "-O no-holes" "" echo -e "\nTesting with compression and with the no-holes feature...\n" test_cloning_inline_extents "-O no-holes" "-o compress" status=0 exit Cc: stable@vger.kernel.org Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
* btrfs: fix use after free iterating extrefsChris Mason2015-11-131-5/+3
| | | | | | | | | | | | | | | | | | | | | | [ Upstream commit dc6c5fb3b514221f2e9d21ee626a9d95d3418dff ] The code for btrfs inode-resolve has never worked properly for files with enough hard links to trigger extrefs. It was trying to get the leaf out of a path after freeing the path: btrfs_release_path(path); leaf = path->nodes[0]; item_size = btrfs_item_size_nr(leaf, slot); The fix here is to use the extent buffer we cloned just a little higher up to avoid deadlocks caused by using the leaf in the path. Signed-off-by: Chris Mason <clm@fb.com> cc: stable@vger.kernel.org # v3.7+ cc: Mark Fasheh <mfasheh@suse.de> Reviewed-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Mark Fasheh <mfasheh@suse.de> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
* Btrfs: update fix for read corruption of compressed and shared extentsFilipe Manana2015-10-271-8/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit 808f80b46790f27e145c72112189d6a3be2bc884 ] My previous fix in commit 005efedf2c7d ("Btrfs: fix read corruption of compressed and shared extents") was effective only if the compressed extents cover a file range with a length that is not a multiple of 16 pages. That's because the detection of when we reached a different range of the file that shares the same compressed extent as the previously processed range was done at extent_io.c:__do_contiguous_readpages(), which covers subranges with a length up to 16 pages, because extent_readpages() groups the pages in clusters no larger than 16 pages. So fix this by tracking the start of the previously processed file range's extent map at extent_readpages(). The following test case for fstests reproduces the issue: seq=`basename $0` seqres=$RESULT_DIR/$seq echo "QA output created by $seq" tmp=/tmp/$$ status=1 # failure is the default! trap "_cleanup; exit \$status" 0 1 2 3 15 _cleanup() { rm -f $tmp.* } # get standard environment, filters and checks . ./common/rc . ./common/filter # real QA test starts here _need_to_be_root _supported_fs btrfs _supported_os Linux _require_scratch _require_cloner rm -f $seqres.full test_clone_and_read_compressed_extent() { local mount_opts=$1 _scratch_mkfs >>$seqres.full 2>&1 _scratch_mount $mount_opts # Create our test file with a single extent of 64Kb that is going to # be compressed no matter which compression algo is used (zlib/lzo). $XFS_IO_PROG -f -c "pwrite -S 0xaa 0K 64K" \ $SCRATCH_MNT/foo | _filter_xfs_io # Now clone the compressed extent into an adjacent file offset. $CLONER_PROG -s 0 -d $((64 * 1024)) -l $((64 * 1024)) \ $SCRATCH_MNT/foo $SCRATCH_MNT/foo echo "File digest before unmount:" md5sum $SCRATCH_MNT/foo | _filter_scratch # Remount the fs or clear the page cache to trigger the bug in # btrfs. Because the extent has an uncompressed length that is a # multiple of 16 pages, all the pages belonging to the second range # of the file (64K to 128K), which points to the same extent as the # first range (0K to 64K), had their contents full of zeroes instead # of the byte 0xaa. This was a bug exclusively in the read path of # compressed extents, the correct data was stored on disk, btrfs # just failed to fill in the pages correctly. _scratch_remount echo "File digest after remount:" # Must match the digest we got before. md5sum $SCRATCH_MNT/foo | _filter_scratch } echo -e "\nTesting with zlib compression..." test_clone_and_read_compressed_extent "-o compress=zlib" _scratch_unmount echo -e "\nTesting with lzo compression..." test_clone_and_read_compressed_extent "-o compress=lzo" status=0 exit Cc: stable@vger.kernel.org Signed-off-by: Filipe Manana <fdmanana@suse.com> Tested-by: Timofey Titovets <nefelim4ag@gmail.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
* Btrfs: fix read corruption of compressed and shared extentsFilipe Manana2015-10-271-8/+57
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit 005efedf2c7d0a270ffbe28d8997b03844f3e3e7 ] If a file has a range pointing to a compressed extent, followed by another range that points to the same compressed extent and a read operation attempts to read both ranges (either completely or part of them), the pages that correspond to the second range are incorrectly filled with zeroes. Consider the following example: File layout [0 - 8K] [8K - 24K] | | | | points to extent X, points to extent X, offset 4K, length of 8K offset 0, length 16K [extent X, compressed length = 4K uncompressed length = 16K] If a readpages() call spans the 2 ranges, a single bio to read the extent is submitted - extent_io.c:submit_extent_page() would only create a new bio to cover the second range pointing to the extent if the extent it points to had a different logical address than the extent associated with the first range. This has a consequence of the compressed read end io handler (compression.c:end_compressed_bio_read()) finish once the extent is decompressed into the pages covering the first range, leaving the remaining pages (belonging to the second range) filled with zeroes (done by compression.c:btrfs_clear_biovec_end()). So fix this by submitting the current bio whenever we find a range pointing to a compressed extent that was preceded by a range with a different extent map. This is the simplest solution for this corner case. Making the end io callback populate both ranges (or more, if we have multiple pointing to the same extent) is a much more complex solution since each bio is tightly coupled with a single extent map and the extent maps associated to the ranges pointing to the shared extent can have different offsets and lengths. The following test case for fstests triggers the issue: seq=`basename $0` seqres=$RESULT_DIR/$seq echo "QA output created by $seq" tmp=/tmp/$$ status=1 # failure is the default! trap "_cleanup; exit \$status" 0 1 2 3 15 _cleanup() { rm -f $tmp.* } # get standard environment, filters and checks . ./common/rc . ./common/filter # real QA test starts here _need_to_be_root _supported_fs btrfs _supported_os Linux _require_scratch _require_cloner rm -f $seqres.full test_clone_and_read_compressed_extent() { local mount_opts=$1 _scratch_mkfs >>$seqres.full 2>&1 _scratch_mount $mount_opts # Create a test file with a single extent that is compressed (the # data we write into it is highly compressible no matter which # compression algorithm is used, zlib or lzo). $XFS_IO_PROG -f -c "pwrite -S 0xaa 0K 4K" \ -c "pwrite -S 0xbb 4K 8K" \ -c "pwrite -S 0xcc 12K 4K" \ $SCRATCH_MNT/foo | _filter_xfs_io # Now clone our extent into an adjacent offset. $CLONER_PROG -s $((4 * 1024)) -d $((16 * 1024)) -l $((8 * 1024)) \ $SCRATCH_MNT/foo $SCRATCH_MNT/foo # Same as before but for this file we clone the extent into a lower # file offset. $XFS_IO_PROG -f -c "pwrite -S 0xaa 8K 4K" \ -c "pwrite -S 0xbb 12K 8K" \ -c "pwrite -S 0xcc 20K 4K" \ $SCRATCH_MNT/bar | _filter_xfs_io $CLONER_PROG -s $((12 * 1024)) -d 0 -l $((8 * 1024)) \ $SCRATCH_MNT/bar $SCRATCH_MNT/bar echo "File digests before unmounting filesystem:" md5sum $SCRATCH_MNT/foo | _filter_scratch md5sum $SCRATCH_MNT/bar | _filter_scratch # Evicting the inode or clearing the page cache before reading # again the file would also trigger the bug - reads were returning # all bytes in the range corresponding to the second reference to # the extent with a value of 0, but the correct data was persisted # (it was a bug exclusively in the read path). The issue happened # only if the same readpages() call targeted pages belonging to the # first and second ranges that point to the same compressed extent. _scratch_remount echo "File digests after mounting filesystem again:" # Must match the same digests we got before. md5sum $SCRATCH_MNT/foo | _filter_scratch md5sum $SCRATCH_MNT/bar | _filter_scratch } echo -e "\nTesting with zlib compression..." test_clone_and_read_compressed_extent "-o compress=zlib" _scratch_unmount echo -e "\nTesting with lzo compression..." test_clone_and_read_compressed_extent "-o compress=lzo" status=0 exit Cc: stable@vger.kernel.org Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Qu Wenruo<quwenruo@cn.fujitsu.com> Reviewed-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
* btrfs: skip waiting on ordered range for special filesJeff Mahoney2015-10-271-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit a30e577c96f59b1e1678ea5462432b09bf7d5cbc ] In btrfs_evict_inode, we properly truncate the page cache for evicted inodes but then we call btrfs_wait_ordered_range for every inode as well. It's the right thing to do for regular files but results in incorrect behavior for device inodes for block devices. filemap_fdatawrite_range gets called with inode->i_mapping which gets resolved to the block device inode before getting passed to wbc_attach_fdatawrite_inode and ultimately to inode_to_bdi. What happens next depends on whether there's an open file handle associated with the inode. If there is, we write to the block device, which is unexpected behavior. If there isn't, we through normally and inode->i_data is used. We can also end up racing against open/close which can result in crashes when i_mapping points to a block device inode that has been closed. Since there can't be any page cache associated with special file inodes, it's safe to skip the btrfs_wait_ordered_range call entirely and avoid the problem. Cc: <stable@vger.kernel.org> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=100911 Tested-by: Christoph Biedl <linux-kernel.bfrz@manchmal.in-ulm.de> Signed-off-by: Jeff Mahoney <jeffm@suse.com> Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
* Btrfs: check if previous transaction aborted to avoid fs corruptionFilipe Manana2015-10-071-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit 1f9b8c8fbc9a4d029760b16f477b9d15500e3a34 ] While we are committing a transaction, it's possible the previous one is still finishing its commit and therefore we wait for it to finish first. However we were not checking if that previous transaction ended up getting aborted after we waited for it to commit, so we ended up committing the current transaction which can lead to fs corruption because the new superblock can point to trees that have had one or more nodes/leafs that were never durably persisted. The following sequence diagram exemplifies how this is possible: CPU 0 CPU 1 transaction N starts (...) btrfs_commit_transaction(N) cur_trans->state = TRANS_STATE_COMMIT_START; (...) cur_trans->state = TRANS_STATE_COMMIT_DOING; (...) cur_trans->state = TRANS_STATE_UNBLOCKED; root->fs_info->running_transaction = NULL; btrfs_start_transaction() --> starts transaction N + 1 btrfs_write_and_wait_transaction(trans, root); --> starts writing all new or COWed ebs created at transaction N creates some new ebs, COWs some existing ebs but doesn't COW or deletes eb X btrfs_commit_transaction(N + 1) (...) cur_trans->state = TRANS_STATE_COMMIT_START; (...) wait_for_commit(root, prev_trans); --> prev_trans == transaction N btrfs_write_and_wait_transaction() continues writing ebs --> fails writing eb X, we abort transaction N and set bit BTRFS_FS_STATE_ERROR on fs_info->fs_state, so no new transactions can start after setting that bit cleanup_transaction() btrfs_cleanup_one_transaction() wakes up task at CPU 1 continues, doesn't abort because cur_trans->aborted (transaction N + 1) is zero, and no checks for bit BTRFS_FS_STATE_ERROR in fs_info->fs_state are made btrfs_write_and_wait_transaction(trans, root); --> succeeds, no errors during writeback write_ctree_super(trans, root, 0); --> succeeds --> we have now a superblock that points us to some root that uses eb X, which was never written to disk In this scenario future attempts to read eb X from disk results in an error message like "parent transid verify failed on X wanted Y found Z". So fix this by aborting the current transaction if after waiting for the previous transaction we verify that it was aborted. Cc: stable@vger.kernel.org Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Josef Bacik <jbacik@fb.com> Reviewed-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: Chris Mason <clm@fb.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
* btrfs: cleanup orphans while looking up default subvolumeJeff Mahoney2015-08-271-0/+9
| | | | | | | | | | | | | | | | [ Upstream commit 727b9784b6085c99c2f836bf4fcc2848dc9cf904 ] Orphans in the fs tree are cleaned up via open_ctree and subvolume orphans are cleaned via btrfs_lookup_dentry -- except when a default subvolume is in use. The name for the default subvolume uses a manual lookup that doesn't trigger orphan cleanup and needs to trigger it manually as well. This doesn't apply to the remount case since the subvolumes are cleaned up by walking the root radix tree. Signed-off-by: Jeff Mahoney <jeffm@suse.com> Reviewed-by: David Sterba <dsterba@suse.cz> Signed-off-by: Chris Mason <clm@fb.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
* btrfs: incorrect handling for fiemap_fill_next_extent returnChengyu Song2015-08-271-1/+4
| | | | | | | | | | | | | | | [ Upstream commit 26e726afe01c1c82072cf23a5ed89ce25f39d9f2 ] fiemap_fill_next_extent returns 0 on success, -errno on error, 1 if this was the last extent that will fit in user array. If 1 is returned, the return value may eventually returned to user space, which should not happen, according to manpage of ioctl. Signed-off-by: Chengyu Song <csong84@gatech.edu> Reviewed-by: David Sterba <dsterba@suse.cz> Reviewed-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: Chris Mason <clm@fb.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
* Btrfs: fix memory leak in the extent_same ioctlFilipe Manana2015-08-041-1/+3
| | | | | | | | | | | | | | | | | | [ Upstream commit 497b4050e0eacd4c746dd396d14916b1e669849d ] We were allocating memory with memdup_user() but we were never releasing that memory. This affected pretty much every call to the ioctl, whether it deduplicated extents or not. This issue was reported on IRC by Julian Taylor and on the mailing list by Marcel Ritter, credit goes to them for finding the issue. Reported-by: Julian Taylor <jtaylor.debian@googlemail.com> Reported-by: Marcel Ritter <ritter.marcel@gmail.com> Cc: stable@vger.kernel.org Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Mark Fasheh <mfasheh@suse.de> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
* Btrfs: use kmem_cache_free when freeing entry in inode cacheFilipe Manana2015-08-041-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit c3f4a1685bb87e59c886ee68f7967eae07d4dffa ] The free space entries are allocated using kmem_cache_zalloc(), through __btrfs_add_free_space(), therefore we should use kmem_cache_free() and not kfree() to avoid any confusion and any potential problem. Looking at the kfree() definition at mm/slab.c it has the following comment: /* * (...) * * Don't free memory not originally allocated by kmalloc() * or you will run into trouble. */ So better be safe and use kmem_cache_free(). Cc: stable@vger.kernel.org Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.cz> Signed-off-by: Chris Mason <clm@fb.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
* Btrfs: make xattr replace operations atomicFilipe Manana2015-07-134-65/+102
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit 02590fd855d1690568b2fa439c942e933221b57a ] commit 5f5bc6b1e2d5a6f827bc860ef2dc5b6f365d1339 upstream. Replacing a xattr consists of doing a lookup for its existing value, delete the current value from the respective leaf, release the search path and then finally insert the new value. This leaves a time window where readers (getxattr, listxattrs) won't see any value for the xattr. Xattrs are used to store ACLs, so this has security implications. This change also fixes 2 other existing issues which were: *) Deleting the old xattr value without verifying first if the new xattr will fit in the existing leaf item (in case multiple xattrs are packed in the same item due to name hash collision); *) Returning -EEXIST when the flag XATTR_CREATE is given and the xattr doesn't exist but we have have an existing item that packs muliple xattrs with the same name hash as the input xattr. In this case we should return ENOSPC. A test case for xfstests follows soon. Thanks to Alexandre Oliva for reporting the non-atomicity of the xattr replace implementation. Reported-by: Alexandre Oliva <oliva@gnu.org> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Chris Mason <clm@fb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
* Btrfs: don't invalidate root dentry when subvolume deletion failsOmar Sandoval2015-07-031-3/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit 64ad6c488975d7516230cf7849190a991fd615ae ] Since commit bafc9b754f75 ("vfs: More precise tests in d_invalidate"), mounted subvolumes can be deleted because d_invalidate() won't fail. However, we run into problems when we attempt to delete the default subvolume while it is mounted as the root filesystem: # btrfs subvol list / ID 257 gen 306 top level 5 path rootvol ID 267 gen 334 top level 5 path snap1 # btrfs subvol get-default / ID 267 gen 334 top level 5 path snap1 # btrfs inspect-internal rootid / 267 # mount -o subvol=/ /dev/vda1 /mnt # btrfs subvol del /mnt/snap1 Delete subvolume (no-commit): '/mnt/snap1' ERROR: cannot delete '/mnt/snap1' - Operation not permitted # findmnt / findmnt: can't read /proc/mounts: No such file or directory # ls /proc # Markus reported that this same scenario simply led to a kernel oops. This happens because in btrfs_ioctl_snap_destroy(), we call d_invalidate() before we check may_destroy_subvol(), which means that we detach the submounts and drop the dentry before erroring out. Instead, we should only invalidate the dentry once the deletion has succeeded. Additionally, the shrink_dcache_sb() isn't necessary; d_invalidate() will prune the dcache for the deleted subvolume. Cc: <stable@vger.kernel.org> Fixes: bafc9b754f75 ("vfs: More precise tests in d_invalidate") Reported-by: Markus Schauler <mschauler@gmail.com> Signed-off-by: Omar Sandoval <osandov@osandov.com> Signed-off-by: Chris Mason <clm@fb.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
* btrfs: unlock i_mutex after attempting to delete subvolume during sendOmar Sandoval2015-05-171-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit 909e26dce3f7600f5e293ac0522c28790a0c8c9c ] Whenever the check for a send in progress introduced in commit 521e0546c970 (btrfs: protect snapshots from deleting during send) is hit, we return without unlocking inode->i_mutex. This is easy to see with lockdep enabled: [ +0.000059] ================================================ [ +0.000028] [ BUG: lock held when returning to user space! ] [ +0.000029] 4.0.0-rc5-00096-g3c435c1 #93 Not tainted [ +0.000026] ------------------------------------------------ [ +0.000029] btrfs/211 is leaving the kernel with locks still held! [ +0.000029] 1 lock held by btrfs/211: [ +0.000023] #0: (&type->i_mutex_dir_key){+.+.+.}, at: [<ffffffff8135b8df>] btrfs_ioctl_snap_destroy+0x2df/0x7a0 Make sure we unlock it in the error path. Reviewed-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.cz> Cc: stable@vger.kernel.org Signed-off-by: Omar Sandoval <osandov@osandov.com> Signed-off-by: Chris Mason <clm@fb.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
* Btrfs: fix inode eviction infinite loop after extent_same ioctlFilipe Manana2015-05-171-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit HEAD ] commit 113e8283869b9855c8b999796aadd506bbac155f upstream. If we pass a length of 0 to the extent_same ioctl, we end up locking an extent range with a start offset greater then its end offset (if the destination file's offset is greater than zero). This results in a warning from extent_io.c:insert_state through the following call chain: btrfs_extent_same() btrfs_double_lock() lock_extent_range() lock_extent(inode->io_tree, offset, offset + len - 1) lock_extent_bits() __set_extent_bit() insert_state() --> WARN_ON(end < start) This leads to an infinite loop when evicting the inode. This is the same problem that my previous patch titled "Btrfs: fix inode eviction infinite loop after cloning into it" addressed but for the extent_same ioctl instead of the clone ioctl. Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Omar Sandoval <osandov@osandov.com> Signed-off-by: Chris Mason <clm@fb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> (cherry picked from commit 9dc106617d5669a6f8d86e08f620dc2fb0413e21) Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
* Btrfs: fix inode eviction infinite loop after cloning into itFilipe Manana2015-05-171-0/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit HEAD ] commit ccccf3d67294714af2d72a6fd6fd7d73b01c9329 upstream. If we attempt to clone a 0 length region into a file we can end up inserting a range in the inode's extent_io tree with a start offset that is greater then the end offset, which triggers immediately the following warning: [ 3914.619057] WARNING: CPU: 17 PID: 4199 at fs/btrfs/extent_io.c:435 insert_state+0x4b/0x10b [btrfs]() [ 3914.620886] BTRFS: end < start 4095 4096 (...) [ 3914.638093] Call Trace: [ 3914.638636] [<ffffffff81425fd9>] dump_stack+0x4c/0x65 [ 3914.639620] [<ffffffff81045390>] warn_slowpath_common+0xa1/0xbb [ 3914.640789] [<ffffffffa03ca44f>] ? insert_state+0x4b/0x10b [btrfs] [ 3914.642041] [<ffffffff810453f0>] warn_slowpath_fmt+0x46/0x48 [ 3914.643236] [<ffffffffa03ca44f>] insert_state+0x4b/0x10b [btrfs] [ 3914.644441] [<ffffffffa03ca729>] __set_extent_bit+0x107/0x3f4 [btrfs] [ 3914.645711] [<ffffffffa03cb256>] lock_extent_bits+0x65/0x1bf [btrfs] [ 3914.646914] [<ffffffff8142b2fb>] ? _raw_spin_unlock+0x28/0x33 [ 3914.648058] [<ffffffffa03cbac4>] ? test_range_bit+0xcc/0xde [btrfs] [ 3914.650105] [<ffffffffa03cb3c3>] lock_extent+0x13/0x15 [btrfs] [ 3914.651361] [<ffffffffa03db39e>] lock_extent_range+0x3d/0xcd [btrfs] [ 3914.652761] [<ffffffffa03de1fe>] btrfs_ioctl_clone+0x278/0x388 [btrfs] [ 3914.654128] [<ffffffff811226dd>] ? might_fault+0x58/0xb5 [ 3914.655320] [<ffffffffa03e0909>] btrfs_ioctl+0xb51/0x2195 [btrfs] (...) [ 3914.669271] ---[ end trace 14843d3e2e622fc1 ]--- This later makes the inode eviction handler enter an infinite loop that keeps dumping the following warning over and over: [ 3915.117629] WARNING: CPU: 22 PID: 4228 at fs/btrfs/extent_io.c:435 insert_state+0x4b/0x10b [btrfs]() [ 3915.119913] BTRFS: end < start 4095 4096 (...) [ 3915.137394] Call Trace: [ 3915.137913] [<ffffffff81425fd9>] dump_stack+0x4c/0x65 [ 3915.139154] [<ffffffff81045390>] warn_slowpath_common+0xa1/0xbb [ 3915.140316] [<ffffffffa03ca44f>] ? insert_state+0x4b/0x10b [btrfs] [ 3915.141505] [<ffffffff810453f0>] warn_slowpath_fmt+0x46/0x48 [ 3915.142709] [<ffffffffa03ca44f>] insert_state+0x4b/0x10b [btrfs] [ 3915.143849] [<ffffffffa03ca729>] __set_extent_bit+0x107/0x3f4 [btrfs] [ 3915.145120] [<ffffffffa038c1e3>] ? btrfs_kill_super+0x17/0x23 [btrfs] [ 3915.146352] [<ffffffff811548f6>] ? deactivate_locked_super+0x3b/0x50 [ 3915.147565] [<ffffffffa03cb256>] lock_extent_bits+0x65/0x1bf [btrfs] [ 3915.148785] [<ffffffff8142b7e2>] ? _raw_write_unlock+0x28/0x33 [ 3915.149931] [<ffffffffa03bc325>] btrfs_evict_inode+0x196/0x482 [btrfs] [ 3915.151154] [<ffffffff81168904>] evict+0xa0/0x148 [ 3915.152094] [<ffffffff811689e5>] dispose_list+0x39/0x43 [ 3915.153081] [<ffffffff81169564>] evict_inodes+0xdc/0xeb [ 3915.154062] [<ffffffff81154418>] generic_shutdown_super+0x49/0xef [ 3915.155193] [<ffffffff811546d1>] kill_anon_super+0x13/0x1e [ 3915.156274] [<ffffffffa038c1e3>] btrfs_kill_super+0x17/0x23 [btrfs] (...) [ 3915.167404] ---[ end trace 14843d3e2e622fc2 ]--- So just bail out of the clone ioctl if the length of the region to clone is zero, without locking any extent range, in order to prevent this issue (same behaviour as a pwrite with a 0 length for example). This is trivial to reproduce. For example, the steps for the test I just made for fstests: mkfs.btrfs -f SCRATCH_DEV mount SCRATCH_DEV $SCRATCH_MNT touch $SCRATCH_MNT/foo touch $SCRATCH_MNT/bar $CLONER_PROG -s 0 -d 4096 -l 0 $SCRATCH_MNT/foo $SCRATCH_MNT/bar umount $SCRATCH_MNT A test case for fstests follows soon. Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Omar Sandoval <osandov@osandov.com> Signed-off-by: Chris Mason <clm@fb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> (cherry picked from commit 449b46275ce58e1d3fc20d1efacd0d0369c6070f) Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
* btrfs: don't accept bare namespace as a valid xattrDavid Sterba2015-05-171-14/+39
| | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit HEAD ] commit 3c3b04d10ff1811a27f86684ccd2f5ba6983211d upstream. Due to insufficient check in btrfs_is_valid_xattr, this unexpectedly works: $ touch file $ setfattr -n user. -v 1 file $ getfattr -d file user.="1" ie. the missing attribute name after the namespace. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=94291 Reported-by: William Douglas <william.douglas@intel.com> Signed-off-by: David Sterba <dsterba@suse.cz> Signed-off-by: Chris Mason <clm@fb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> (cherry picked from commit 1bb2835ed4f8ee186d8110817cf5a96ef9e35ab3) Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
* Btrfs: fix log tree corruption when fs mounted with -o discardFilipe Manana2015-05-171-3/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit HEAD ] commit dcc82f4783ad91d4ab654f89f37ae9291cdc846a upstream. While committing a transaction we free the log roots before we write the new super block. Freeing the log roots implies marking the disk location of every node/leaf (metadata extent) as pinned before the new super block is written. This is to prevent the disk location of log metadata extents from being reused before the new super block is written, otherwise we would have a corrupted log tree if before the new super block is written a crash/reboot happens and the location of any log tree metadata extent ended up being reused and rewritten. Even though we pinned the log tree's metadata extents, we were issuing a discard against them if the fs was mounted with the -o discard option, resulting in corruption of the log tree if a crash/reboot happened before writing the new super block - the next time the fs was mounted, during the log replay process we would find nodes/leafs of the log btree with a content full of zeroes, causing the process to fail and require the use of the tool btrfs-zero-log to wipeout the log tree (and all data previously fsynced becoming lost forever). Fix this by not doing a discard when pinning an extent. The discard will be done later when it's safe (after the new super block is committed) at extent-tree.c:btrfs_finish_extent_commit(). Fixes: e688b7252f78 (Btrfs: fix extent pinning bugs in the tree log) Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Chris Mason <clm@fb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> (cherry picked from commit 3909e5a93ed64a186a396c1b7fd1db07e065728f) Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
* btrfs: simplify insert_orphan_itemDavid Sterba2015-04-231-12/+4
| | | | | | | | | | [ Upstream commit 9c4f61f01d269815bb7c37be3ede59c5587747c6 ] We can search and add the orphan item in one go, btrfs_insert_orphan_item will find out if the item already exists. Signed-off-by: David Sterba <dsterba@suse.cz> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
* Btrfs:__add_inode_ref: out of bounds memory read when looking for extended ref.Quentin Casasnovas2015-03-141-1/+1
| | | | | | | | | | | | commit dd9ef135e3542ffc621c4eb7f0091870ec7a1504 upstream. Improper arithmetics when calculting the address of the extended ref could lead to an out of bounds memory read and kernel panic. Signed-off-by: Quentin Casasnovas <quentin.casasnovas@oracle.com> Reviewed-by: David Sterba <dsterba@suse.cz> Signed-off-by: Chris Mason <clm@fb.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
* Btrfs: fix data loss in the fast fsync pathFilipe Manana2015-03-141-28/+28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 3a8b36f378060d20062a0918e99fae39ff077bf0 upstream. When using the fast file fsync code path we can miss the fact that new writes happened since the last file fsync and therefore return without waiting for the IO to finish and write the new extents to the fsync log. Here's an example scenario where the fsync will miss the fact that new file data exists that wasn't yet durably persisted: 1. fs_info->last_trans_committed == N - 1 and current transaction is transaction N (fs_info->generation == N); 2. do a buffered write; 3. fsync our inode, this clears our inode's full sync flag, starts an ordered extent and waits for it to complete - when it completes at btrfs_finish_ordered_io(), the inode's last_trans is set to the value N (via btrfs_update_inode_fallback -> btrfs_update_inode -> btrfs_set_inode_last_trans); 4. transaction N is committed, so fs_info->last_trans_committed is now set to the value N and fs_info->generation remains with the value N; 5. do another buffered write, when this happens btrfs_file_write_iter sets our inode's last_trans to the value N + 1 (that is fs_info->generation + 1 == N + 1); 6. transaction N + 1 is started and fs_info->generation now has the value N + 1; 7. transaction N + 1 is committed, so fs_info->last_trans_committed is set to the value N + 1; 8. fsync our inode - because it doesn't have the full sync flag set, we only start the ordered extent, we don't wait for it to complete (only in a later phase) therefore its last_trans field has the value N + 1 set previously by btrfs_file_write_iter(), and so we have: inode->last_trans <= fs_info->last_trans_committed (N + 1) (N + 1) Which made us not log the last buffered write and exit the fsync handler immediately, returning success (0) to user space and resulting in data loss after a crash. This can actually be triggered deterministically and the following excerpt from a testcase I made for xfstests triggers the issue. It moves a dummy file across directories and then fsyncs the old parent directory - this is just to trigger a transaction commit, so moving files around isn't directly related to the issue but it was chosen because running 'sync' for example does more than just committing the current transaction, as it flushes/waits for all file data to be persisted. The issue can also happen at random periods, since the transaction kthread periodicaly commits the current transaction (about every 30 seconds by default). The body of the test is: _scratch_mkfs >> $seqres.full 2>&1 _init_flakey _mount_flakey # Create our main test file 'foo', the one we check for data loss. # By doing an fsync against our file, it makes btrfs clear the 'needs_full_sync' # bit from its flags (btrfs inode specific flags). $XFS_IO_PROG -f -c "pwrite -S 0xaa 0 8K" \ -c "fsync" $SCRATCH_MNT/foo | _filter_xfs_io # Now create one other file and 2 directories. We will move this second file # from one directory to the other later because it forces btrfs to commit its # currently open transaction if we fsync the old parent directory. This is # necessary to trigger the data loss bug that affected btrfs. mkdir $SCRATCH_MNT/testdir_1 touch $SCRATCH_MNT/testdir_1/bar mkdir $SCRATCH_MNT/testdir_2 # Make sure everything is durably persisted. sync # Write more 8Kb of data to our file. $XFS_IO_PROG -c "pwrite -S 0xbb 8K 8K" $SCRATCH_MNT/foo | _filter_xfs_io # Move our 'bar' file into a new directory. mv $SCRATCH_MNT/testdir_1/bar $SCRATCH_MNT/testdir_2/bar # Fsync our first directory. Because it had a file moved into some other # directory, this made btrfs commit the currently open transaction. This is # a condition necessary to trigger the data loss bug. $XFS_IO_PROG -c "fsync" $SCRATCH_MNT/testdir_1 # Now fsync our main test file. If the fsync succeeds, we expect the 8Kb of # data we wrote previously to be persisted and available if a crash happens. # This did not happen with btrfs, because of the transaction commit that # happened when we fsynced the parent directory. $XFS_IO_PROG -c "fsync" $SCRATCH_MNT/foo # Simulate a crash/power loss. _load_flakey_table $FLAKEY_DROP_WRITES _unmount_flakey _load_flakey_table $FLAKEY_ALLOW_WRITES _mount_flakey # Now check that all data we wrote before are available. echo "File content after log replay:" od -t x1 $SCRATCH_MNT/foo status=0 exit The expected golden output for the test, which is what we get with this fix applied (or when running against ext3/4 and xfs), is: wrote 8192/8192 bytes at offset 0 XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) wrote 8192/8192 bytes at offset 8192 XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) File content after log replay: 0000000 aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa * 0020000 bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb * 0040000 Without this fix applied, the output shows the test file does not have the second 8Kb extent that we successfully fsynced: wrote 8192/8192 bytes at offset 0 XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) wrote 8192/8192 bytes at offset 8192 XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) File content after log replay: 0000000 aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa * 0020000 So fix this by skipping the fsync only if we're doing a full sync and if the inode's last_trans is <= fs_info->last_trans_committed, or if the inode is already in the log. Also remove setting the inode's last_trans in btrfs_file_write_iter since it's useless/unreliable. Also because btrfs_file_write_iter no longer sets inode->last_trans to fs_info->generation + 1, don't set last_trans to 0 if we bail out and don't bail out if last_trans is 0, otherwise something as simple as the following example wouldn't log the second write on the last fsync: 1. write to file 2. fsync file 3. fsync file |--> btrfs_inode_in_log() returns true and it set last_trans to 0 4. write to file |--> btrfs_file_write_iter() no longers sets last_trans, so it remained with a value of 0 5. fsync |--> inode->last_trans == 0, so it bails out without logging the second write A test case for xfstests will be sent soon. Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Chris Mason <clm@fb.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
* btrfs: fix lost return value due to variable shadowingDavid Sterba2015-03-141-1/+0
| | | | | | | | | | | | commit 1932b7be973b554ffe20a5bba6ffaed6fa995cdc upstream. A block-local variable stores error code but btrfs_get_blocks_direct may not return it in the end as there's a ret defined in the function scope. Fixes: d187663ef24c ("Btrfs: lock extents as we map them in DIO") Signed-off-by: David Sterba <dsterba@suse.cz> Signed-off-by: Chris Mason <clm@fb.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
* Btrfs: fix fsync race leading to ordered extent memory leaksFilipe Manana2015-03-141-5/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 4d884fceaa2c838abb598778813e93f6d9fea723 upstream. We can have multiple fsync operations against the same file during the same transaction and they can collect the same ordered extents while they don't complete (still accessible from the inode's ordered tree). If this happens, those ordered extents will never get their reference counts decremented to 0, leading to memory leaks and inode leaks (an iput for an ordered extent's inode is scheduled only when the ordered extent's refcount drops to 0). The following sequence diagram explains this race: CPU 1 CPU 2 btrfs_sync_file() btrfs_sync_file() mutex_lock(inode->i_mutex) btrfs_log_inode() btrfs_get_logged_extents() --> collects ordered extent X --> increments ordered extent X's refcount btrfs_submit_logged_extents() mutex_unlock(inode->i_mutex) mutex_lock(inode->i_mutex) btrfs_sync_log() btrfs_wait_logged_extents() --> list_del_init(&ordered->log_list) btrfs_log_inode() btrfs_get_logged_extents() --> Adds ordered extent X to logged_list because at this point: list_empty(&ordered->log_list) && test_bit(BTRFS_ORDERED_LOGGED, &ordered->flags) == 0 --> Increments ordered extent X's refcount --> check if ordered extent's io is finished or not, start it if necessary and wait for it to finish --> sets bit BTRFS_ORDERED_LOGGED on ordered extent X's flags and adds it to trans->ordered btrfs_sync_log() finishes btrfs_submit_logged_extents() btrfs_log_inode() finishes mutex_unlock(inode->i_mutex) btrfs_sync_file() finishes btrfs_sync_log() btrfs_wait_logged_extents() --> Sees ordered extent X has the bit BTRFS_ORDERED_LOGGED set in its flags --> X's refcount is untouched btrfs_sync_log() finishes btrfs_sync_file() finishes btrfs_commit_transaction() --> called by transaction kthread for e.g. btrfs_wait_pending_ordered() --> waits for ordered extent X to complete --> decrements ordered extent X's refcount by 1 only, corresponding to the increment done by the fsync task ran by CPU 1 In the scenario of the above diagram, after the transaction commit, the ordered extent will remain with a refcount of 1 forever, leaking the ordered extent structure and preventing the i_count of its inode from ever decreasing to 0, since the delayed iput is scheduled only when the ordered extent's refcount drops to 0, preventing the inode from ever being evicted by the VFS. Fix this by using the flag BTRFS_ORDERED_LOGGED differently. Use it to mean that an ordered extent is already being processed by an fsync call, which will attach it to the current transaction, preventing it from being collected by subsequent fsync operations against the same inode. This race was introduced with the following change (added in 3.19 and backported to stable 3.18 and 3.17): Btrfs: make sure logged extents complete in the current transaction V3 commit 50d9aa99bd35c77200e0e3dd7a72274f8304701f I ran into this issue while running xfstests/generic/113 in a loop, which failed about 1 out of 10 runs with the following warning in dmesg: [ 2612.440038] WARNING: CPU: 4 PID: 22057 at fs/btrfs/disk-io.c:3558 free_fs_root+0x36/0x133 [btrfs]() [ 2612.442810] Modules linked in: btrfs crc32c_generic xor raid6_pq nfsd auth_rpcgss oid_registry nfs_acl nfs lockd grace fscache sunrpc loop processor parport_pc parport psmouse therma l_sys i2c_piix4 serio_raw pcspkr evdev microcode button i2c_core ext4 crc16 jbd2 mbcache sd_mod sg sr_mod cdrom virtio_scsi ata_generic virtio_pci ata_piix virtio_ring libata virtio flo ppy e1000 scsi_mod [last unloaded: btrfs] [ 2612.452711] CPU: 4 PID: 22057 Comm: umount Tainted: G W 3.19.0-rc5-btrfs-next-4+ #1 [ 2612.454921] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5-0-ge51488c-20140602_164612-nilsson.home.kraxel.org 04/01/2014 [ 2612.457709] 0000000000000009 ffff8801342c3c78 ffffffff8142425e ffff88023ec8f2d8 [ 2612.459829] 0000000000000000 ffff8801342c3cb8 ffffffff81045308 ffff880046460000 [ 2612.461564] ffffffffa036da56 ffff88003d07b000 ffff880046460000 ffff880046460068 [ 2612.463163] Call Trace: [ 2612.463719] [<ffffffff8142425e>] dump_stack+0x4c/0x65 [ 2612.464789] [<ffffffff81045308>] warn_slowpath_common+0xa1/0xbb [ 2612.466026] [<ffffffffa036da56>] ? free_fs_root+0x36/0x133 [btrfs] [ 2612.467247] [<ffffffff810453c5>] warn_slowpath_null+0x1a/0x1c [ 2612.468416] [<ffffffffa036da56>] free_fs_root+0x36/0x133 [btrfs] [ 2612.469625] [<ffffffffa036f2a7>] btrfs_drop_and_free_fs_root+0x93/0x9b [btrfs] [ 2612.471251] [<ffffffffa036f353>] btrfs_free_fs_roots+0xa4/0xd6 [btrfs] [ 2612.472536] [<ffffffff8142612e>] ? wait_for_completion+0x24/0x26 [ 2612.473742] [<ffffffffa0370bbc>] close_ctree+0x1f3/0x33c [btrfs] [ 2612.475477] [<ffffffff81059d1d>] ? destroy_workqueue+0x148/0x1ba [ 2612.476695] [<ffffffffa034e3da>] btrfs_put_super+0x19/0x1b [btrfs] [ 2612.477911] [<ffffffff81153e53>] generic_shutdown_super+0x73/0xef [ 2612.479106] [<ffffffff811540e2>] kill_anon_super+0x13/0x1e [ 2612.480226] [<ffffffffa034e1e3>] btrfs_kill_super+0x17/0x23 [btrfs] [ 2612.481471] [<ffffffff81154307>] deactivate_locked_super+0x3b/0x50 [ 2612.482686] [<ffffffff811547a7>] deactivate_super+0x3f/0x43 [ 2612.483791] [<ffffffff8116b3ed>] cleanup_mnt+0x59/0x78 [ 2612.484842] [<ffffffff8116b44c>] __cleanup_mnt+0x12/0x14 [ 2612.485900] [<ffffffff8105d019>] task_work_run+0x8f/0xbc [ 2612.486960] [<ffffffff810028d8>] do_notify_resume+0x5a/0x6b [ 2612.488083] [<ffffffff81236e5b>] ? trace_hardirqs_on_thunk+0x3a/0x3f [ 2612.489333] [<ffffffff8142a17f>] int_signal+0x12/0x17 [ 2612.490353] ---[ end trace 54a960a6bdcb8d93 ]--- [ 2612.557253] VFS: Busy inodes after unmount of sdb. Self-destruct in 5 seconds. Have a nice day... Kmemleak confirmed the ordered extent leak (and btrfs inode specific structures such as delayed nodes): $ cat /sys/kernel/debug/kmemleak unreferenced object 0xffff880154290db0 (size 576): comm "btrfsck", pid 21980, jiffies 4295542503 (age 1273.412s) hex dump (first 32 bytes): 01 40 00 00 01 00 00 00 b0 1d f1 4e 01 88 ff ff .@.........N.... 00 00 00 00 00 00 00 00 c8 0d 29 54 01 88 ff ff ..........)T.... backtrace: [<ffffffff8141d74d>] kmemleak_update_trace+0x4c/0x6a [<ffffffff8122f2c0>] radix_tree_node_alloc+0x6d/0x83 [<ffffffff8122fb26>] __radix_tree_create+0x109/0x190 [<ffffffff8122fbdd>] radix_tree_insert+0x30/0xac [<ffffffffa03b9bde>] btrfs_get_or_create_delayed_node+0x130/0x187 [btrfs] [<ffffffffa03bb82d>] btrfs_delayed_delete_inode_ref+0x32/0xac [btrfs] [<ffffffffa0379dae>] __btrfs_unlink_inode+0xee/0x288 [btrfs] [<ffffffffa037c715>] btrfs_unlink_inode+0x1e/0x40 [btrfs] [<ffffffffa037c797>] btrfs_unlink+0x60/0x9b [btrfs] [<ffffffff8115d7f0>] vfs_unlink+0x9c/0xed [<ffffffff8115f5de>] do_unlinkat+0x12c/0x1fa [<ffffffff811601a7>] SyS_unlinkat+0x29/0x2b [<ffffffff81429e92>] system_call_fastpath+0x12/0x17 [<ffffffffffffffff>] 0xffffffffffffffff unreferenced object 0xffff88014ef11db0 (size 576): comm "rm", pid 22009, jiffies 4295542593 (age 1273.052s) hex dump (first 32 bytes): 02 00 00 00 01 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 c8 1d f1 4e 01 88 ff ff ...........N.... backtrace: [<ffffffff8141d74d>] kmemleak_update_trace+0x4c/0x6a [<ffffffff8122f2c0>] radix_tree_node_alloc+0x6d/0x83 [<ffffffff8122fb26>] __radix_tree_create+0x109/0x190 [<ffffffff8122fbdd>] radix_tree_insert+0x30/0xac [<ffffffffa03b9bde>] btrfs_get_or_create_delayed_node+0x130/0x187 [btrfs] [<ffffffffa03bb82d>] btrfs_delayed_delete_inode_ref+0x32/0xac [btrfs] [<ffffffffa0379dae>] __btrfs_unlink_inode+0xee/0x288 [btrfs] [<ffffffffa037c715>] btrfs_unlink_inode+0x1e/0x40 [btrfs] [<ffffffffa037c797>] btrfs_unlink+0x60/0x9b [btrfs] [<ffffffff8115d7f0>] vfs_unlink+0x9c/0xed [<ffffffff8115f5de>] do_unlinkat+0x12c/0x1fa [<ffffffff811601a7>] SyS_unlinkat+0x29/0x2b [<ffffffff81429e92>] system_call_fastpath+0x12/0x17 [<ffffffffffffffff>] 0xffffffffffffffff unreferenced object 0xffff8800336feda8 (size 584): comm "aio-stress", pid 22031, jiffies 4295543006 (age 1271.400s) hex dump (first 32 bytes): 00 40 3e 00 00 00 00 00 00 00 8f 42 00 00 00 00 .@>........B.... 00 00 01 00 00 00 00 00 00 00 01 00 00 00 00 00 ................ backtrace: [<ffffffff8114eb34>] create_object+0x172/0x29a [<ffffffff8141d790>] kmemleak_alloc+0x25/0x41 [<ffffffff81141ae6>] kmemleak_alloc_recursive.constprop.52+0x16/0x18 [<ffffffff81145288>] kmem_cache_alloc+0xf7/0x198 [<ffffffffa0389243>] __btrfs_add_ordered_extent+0x43/0x309 [btrfs] [<ffffffffa038968b>] btrfs_add_ordered_extent_dio+0x12/0x14 [btrfs] [<ffffffffa03810e2>] btrfs_get_blocks_direct+0x3ef/0x571 [btrfs] [<ffffffff81181349>] do_blockdev_direct_IO+0x62a/0xb47 [<ffffffff8118189a>] __blockdev_direct_IO+0x34/0x36 [<ffffffffa03776e5>] btrfs_direct_IO+0x16a/0x1e8 [btrfs] [<ffffffff81100373>] generic_file_direct_write+0xb8/0x12d [<ffffffffa038615c>] btrfs_file_write_iter+0x24b/0x42f [btrfs] [<ffffffff8118bb0d>] aio_run_iocb+0x2b7/0x32e [<ffffffff8118c99a>] do_io_submit+0x26e/0x2ff [<ffffffff8118ca3b>] SyS_io_submit+0x10/0x12 [<ffffffff81429e92>] system_call_fastpath+0x12/0x17 Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Chris Mason <clm@fb.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
* Btrfs: fix fsync data loss after adding hard link to inodeFilipe Manana2015-03-061-9/+73
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 1a4bcf470c886b955adf36486f4c86f2441d85cb upstream. We have a scenario where after the fsync log replay we can lose file data that had been previously fsync'ed if we added an hard link for our inode and after that we sync'ed the fsync log (for example by fsync'ing some other file or directory). This is because when adding an hard link we updated the inode item in the log tree with an i_size value of 0. At that point the new inode item was in memory only and a subsequent fsync log replay would not make us lose the file data. However if after adding the hard link we sync the log tree to disk, by fsync'ing some other file or directory for example, we ended up losing the file data after log replay, because the inode item in the persisted log tree had an an i_size of zero. This is easy to reproduce, and the following excerpt from my test for xfstests shows this: _scratch_mkfs >> $seqres.full 2>&1 _init_flakey _mount_flakey # Create one file with data and fsync it. # This made the btrfs fsync log persist the data and the inode metadata with # a correct inode->i_size (4096 bytes). $XFS_IO_PROG -f -c "pwrite -S 0xaa -b 4K 0 4K" -c "fsync" \ $SCRATCH_MNT/foo | _filter_xfs_io # Now add one hard link to our file. This made the btrfs code update the fsync # log, in memory only, with an inode metadata having a size of 0. ln $SCRATCH_MNT/foo $SCRATCH_MNT/foo_link # Now force persistence of the fsync log to disk, for example, by fsyncing some # other file. touch $SCRATCH_MNT/bar $XFS_IO_PROG -c "fsync" $SCRATCH_MNT/bar # Before a power loss or crash, we could read the 4Kb of data from our file as # expected. echo "File content before:" od -t x1 $SCRATCH_MNT/foo # Simulate a crash/power loss. _load_flakey_table $FLAKEY_DROP_WRITES _unmount_flakey _load_flakey_table $FLAKEY_ALLOW_WRITES _mount_flakey # After the fsync log replay, because the fsync log had a value of 0 for our # inode's i_size, we couldn't read anymore the 4Kb of data that we previously # wrote and fsync'ed. The size of the file became 0 after the fsync log replay. echo "File content after:" od -t x1 $SCRATCH_MNT/foo Another alternative test, that doesn't need to fsync an inode in the same transaction it was created, is: _scratch_mkfs >> $seqres.full 2>&1 _init_flakey _mount_flakey # Create our test file with some data. $XFS_IO_PROG -f -c "pwrite -S 0xaa -b 8K 0 8K" \ $SCRATCH_MNT/foo | _filter_xfs_io # Make sure the file is durably persisted. sync # Append some data to our file, to increase its size. $XFS_IO_PROG -f -c "pwrite -S 0xcc -b 4K 8K 4K" \ $SCRATCH_MNT/foo | _filter_xfs_io # Fsync the file, so from this point on if a crash/power failure happens, our # new data is guaranteed to be there next time the fs is mounted. $XFS_IO_PROG -c "fsync" $SCRATCH_MNT/foo # Add one hard link to our file. This made btrfs write into the in memory fsync # log a special inode with generation 0 and an i_size of 0 too. Note that this # didn't update the inode in the fsync log on disk. ln $SCRATCH_MNT/foo $SCRATCH_MNT/foo_link # Now make sure the in memory fsync log is durably persisted. # Creating and fsync'ing another file will do it. touch $SCRATCH_MNT/bar $XFS_IO_PROG -c "fsync" $SCRATCH_MNT/bar # As expected, before the crash/power failure, we should be able to read the # 12Kb of file data. echo "File content before:" od -t x1 $SCRATCH_MNT/foo # Simulate a crash/power loss. _load_flakey_table $FLAKEY_DROP_WRITES _unmount_flakey _load_flakey_table $FLAKEY_ALLOW_WRITES _mount_flakey # After mounting the fs again, the fsync log was replayed. # The btrfs fsync log replay code didn't update the i_size of the persisted # inode because the inode item in the log had a special generation with a # value of 0 (and it couldn't know the correct i_size, since that inode item # had a 0 i_size too). This made the last 4Kb of file data inaccessible and # effectively lost. echo "File content after:" od -t x1 $SCRATCH_MNT/foo This isn't a new issue/regression. This problem has been around since the log tree code was added in 2008: Btrfs: Add a write ahead tree log to optimize synchronous operations (commit e02119d5a7b4396c5a872582fddc8bd6d305a70a) Test cases for xfstests follow soon. Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Chris Mason <clm@fb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* btrfs: fix leak of path in btrfs_find_itemDavid Sterba2015-03-063-15/+22
| | | | | | | | | | | | | | | commit 381cf6587f8a8a8e981bc0c1aaaa8859b51dc756 upstream. If btrfs_find_item is called with NULL path it allocates one locally but does not free it. Affected paths are inserting an orphan item for a file and for a subvol root. Move the path allocation to the callers. Fixes: 3f870c289900 ("btrfs: expand btrfs_find_item() to include find_orphan_item functionality") Signed-off-by: David Sterba <dsterba@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* btrfs: set proper message level for skinny metadataDavid Sterba2015-03-061-1/+1
| | | | | | | | | | | | commit 5efa0490cc94aee06cd8d282683e22a8ce0a0026 upstream. This has been confusing people for too long, the message is really just informative. Signed-off-by: David Sterba <dsterba@suse.cz> Signed-off-by: Chris Mason <clm@fb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Btrfs: don't delay inode ref updates during log replayChris Mason2015-01-161-0/+8
| | | | | | | | | | | | | | | | | | | | | | | | | commit 6f8960541b1eb6054a642da48daae2320fddba93 upstream. Commit 1d52c78afbb (Btrfs: try not to ENOSPC on log replay) added a check to skip delayed inode updates during log replay because it confuses the enospc code. But the delayed processing will end up ignoring delayed refs from log replay because the inode itself wasn't put through the delayed code. This can end up triggering a warning at commit time: WARNING: CPU: 2 PID: 778 at fs/btrfs/delayed-inode.c:1410 btrfs_assert_delayed_root_empty+0x32/0x34() Which is repeated for each commit because we never process the delayed inode ref update. The fix used here is to change btrfs_delayed_delete_inode_ref to return an error if we're currently in log replay. The caller will do the ref deletion immediately and everything will work properly. Signed-off-by: Chris Mason <clm@fb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Btrfs: fix fs corruption on transaction abort if device supports discardFilipe Manana2015-01-082-10/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 678886bdc6378c1cbd5072da2c5a3035000214e3 upstream. When we abort a transaction we iterate over all the ranges marked as dirty in fs_info->freed_extents[0] and fs_info->freed_extents[1], clear them from those trees, add them back (unpin) to the free space caches and, if the fs was mounted with "-o discard", perform a discard on those regions. Also, after adding the regions to the free space caches, a fitrim ioctl call can see those ranges in a block group's free space cache and perform a discard on the ranges, so the same issue can happen without "-o discard" as well. This causes corruption, affecting one or multiple btree nodes (in the worst case leaving the fs unmountable) because some of those ranges (the ones in the fs_info->pinned_extents tree) correspond to btree nodes/leafs that are referred by the last committed super block - breaking the rule that anything that was committed by a transaction is untouched until the next transaction commits successfully. I ran into this while running in a loop (for several hours) the fstest that I recently submitted: [PATCH] fstests: add btrfs test to stress chunk allocation/removal and fstrim The corruption always happened when a transaction aborted and then fsck complained like this: _check_btrfs_filesystem: filesystem on /dev/sdc is inconsistent *** fsck.btrfs output *** Check tree block failed, want=94945280, have=0 Check tree block failed, want=94945280, have=0 Check tree block failed, want=94945280, have=0 Check tree block failed, want=94945280, have=0 Check tree block failed, want=94945280, have=0 read block failed check_tree_block Couldn't open file system In this case 94945280 corresponded to the root of a tree. Using frace what I observed was the following sequence of steps happened: 1) transaction N started, fs_info->pinned_extents pointed to fs_info->freed_extents[0]; 2) node/eb 94945280 is created; 3) eb is persisted to disk; 4) transaction N commit starts, fs_info->pinned_extents now points to fs_info->freed_extents[1], and transaction N completes; 5) transaction N + 1 starts; 6) eb is COWed, and btrfs_free_tree_block() called for this eb; 7) eb range (94945280 to 94945280 + 16Kb) is added to fs_info->pinned_extents (fs_info->freed_extents[1]); 8) Something goes wrong in transaction N + 1, like hitting ENOSPC for example, and the transaction is aborted, turning the fs into readonly mode. The stack trace I got for example: [112065.253935] [<ffffffff8140c7b6>] dump_stack+0x4d/0x66 [112065.254271] [<ffffffff81042984>] warn_slowpath_common+0x7f/0x98 [112065.254567] [<ffffffffa0325990>] ? __btrfs_abort_transaction+0x50/0x10b [btrfs] [112065.261674] [<ffffffff810429e5>] warn_slowpath_fmt+0x48/0x50 [112065.261922] [<ffffffffa032949e>] ? btrfs_free_path+0x26/0x29 [btrfs] [112065.262211] [<ffffffffa0325990>] __btrfs_abort_transaction+0x50/0x10b [btrfs] [112065.262545] [<ffffffffa036b1d6>] btrfs_remove_chunk+0x537/0x58b [btrfs] [112065.262771] [<ffffffffa033840f>] btrfs_delete_unused_bgs+0x1de/0x21b [btrfs] [112065.263105] [<ffffffffa0343106>] cleaner_kthread+0x100/0x12f [btrfs] (...) [112065.264493] ---[ end trace dd7903a975a31a08 ]--- [112065.264673] BTRFS: error (device sdc) in btrfs_remove_chunk:2625: errno=-28 No space left [112065.264997] BTRFS info (device sdc): forced readonly 9) The clear kthread sees that the BTRFS_FS_STATE_ERROR bit is set in fs_info->fs_state and calls btrfs_cleanup_transaction(), which in turn calls btrfs_destroy_pinned_extent(); 10) Then btrfs_destroy_pinned_extent() iterates over all the ranges marked as dirty in fs_info->freed_extents[], and for each one it calls discard, if the fs was mounted with "-o discard", and adds the range to the free space cache of the respective block group; 11) btrfs_trim_block_group(), invoked from the fitrim ioctl code path, sees the free space entries and performs a discard; 12) After an umount and mount (or fsck), our eb's location on disk was full of zeroes, and it should have been untouched, because it was marked as dirty in the fs_info->pinned_extents tree, and therefore used by the trees that the last committed superblock points to. Fix this by not performing a discard and not adding the ranges to the free space caches - it's useless from this point since the fs is now in readonly mode and we won't write free space caches to disk anymore (otherwise we would leak space) nor any new superblock. By not adding the ranges to the free space caches, it prevents other code paths from allocating that space and write to it as well, therefore being safer and simpler. This isn't a new problem, as it's been present since 2011 (git commit acce952b0263825da32cf10489413dec78053347). Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Chris Mason <clm@fb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Btrfs: make sure logged extents complete in the current transaction V3Josef Bacik2015-01-086-6/+72
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 50d9aa99bd35c77200e0e3dd7a72274f8304701f upstream. Liu Bo pointed out that my previous fix would lose the generation update in the scenario I described. It is actually much worse than that, we could lose the entire extent if we lose power right after the transaction commits. Consider the following write extent 0-4k log extent in log tree commit transaction < power fail happens here ordered extent completes We would lose the 0-4k extent because it hasn't updated the actual fs tree, and the transaction commit will reset the log so it isn't replayed. If we lose power before the transaction commit we are save, otherwise we are not. Fix this by keeping track of all extents we logged in this transaction. Then when we go to commit the transaction make sure we wait for all of those ordered extents to complete before proceeding. This will make sure that if we lose power after the transaction commit we still have our data. This also fixes the problem of the improperly updated extent generation. Thanks, Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Btrfs: do not move em to modified list when unpinningJosef Bacik2015-01-081-2/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit a28046956c71985046474283fa3bcd256915fb72 upstream. We use the modified list to keep track of which extents have been modified so we know which ones are candidates for logging at fsync() time. Newly modified extents are added to the list at modification time, around the same time the ordered extent is created. We do this so that we don't have to wait for ordered extents to complete before we know what we need to log. The problem is when something like this happens log extent 0-4k on inode 1 copy csum for 0-4k from ordered extent into log sync log commit transaction log some other extent on inode 1 ordered extent for 0-4k completes and adds itself onto modified list again log changed extents see ordered extent for 0-4k has already been logged at this point we assume the csum has been copied sync log crash On replay we will see the extent 0-4k in the log, drop the original 0-4k extent which is the same one that we are replaying which also drops the csum, and then we won't find the csum in the log for that bytenr. This of course causes us to have errors about not having csums for certain ranges of our inode. So remove the modified list manipulation in unpin_extent_cache, any modified extents should have been added well before now, and we don't want them re-logged. This fixes my test that I could reliably reproduce this problem with. Thanks, Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* btrfs: fix wrong accounting of raid1 data profile in statfsDavid Sterba2015-01-081-1/+1
| | | | | | | | | | | | | | | commit 0d95c1bec906dd1ad951c9c001e798ca52baeb0f upstream. The sizes that are obtained from space infos are in raw units and have to be adjusted according to the raid factor. This was missing for f_bavail and df reported doubled size for raid1. Reported-by: Martin Steigerwald <Martin@lichtvoll.de> Fixes: ba7b6e62f420 ("btrfs: adjust statfs calculations according to raid profiles") Signed-off-by: David Sterba <dsterba@suse.cz> Signed-off-by: Chris Mason <clm@fb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Btrfs: make sure we wait on logged extents when fsycning two subvolsJosef Bacik2015-01-081-1/+1
| | | | | | | | | | | | | | | | commit 9dba8cf128ef98257ca719722280c9634e7e9dc7 upstream. If we have two fsync()'s race on different subvols one will do all of its work to get into the log_tree, wait on it's outstanding IO, and then allow the log_tree to finish it's commit. The problem is we were just free'ing that subvols logged extents instead of waiting on them, so whoever lost the race wouldn't really have their data on disk. Fix this by waiting properly instead of freeing the logged extents. Thanks, Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>