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* ext4: drop ext4dev compatEric Sandeen2009-10-011-31/+0
| | | | | | | | Kconfig & super.c promised it'd be gone by 2.6.31, so it's about time to drop it. Signed-off-by: Eric Sandeen <sandeen@redhat.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* ext4: Use tracepoints for mb_history trace fileTheodore Ts'o2009-09-301-17/+1
| | | | | | | | | | | | | | The /proc/fs/ext4/<dev>/mb_history was maintained manually, and had a number of problems: it required a largish amount of memory to be allocated for each ext4 filesystem, and the s_mb_history_lock introduced a CPU contention problem. By ripping out the mb_history code and replacing it with ftrace tracepoints, and we get more functionality: timestamps, event filtering, the ability to correlate mballoc history with other ext4 tracepoints, etc. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* ext4, jbd2: Drop unneeded printks at mount and unmount timeTheodore Ts'o2009-09-291-13/+4
| | | | | | | | | | | There are a number of kernel printk's which are printed when an ext4 filesystem is mounted and unmounted. Disable them to economize space in the system logs. In addition, disabling the mballoc stats by default saves a number of unneeded atomic operations for every block allocation or deallocation. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* ext4: Handle nested ext4_journal_start/stop calls without a journalCurt Wohlgemuth2009-09-291-10/+32
| | | | | | | | This patch fixes a problem with handling nested calls to ext4_journal_start/ext4_journal_stop, when there is no journal present. Signed-off-by: Curt Wohlgemuth <curtw@google.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* ext4: async direct IO for holes and fallocate supportMingming Cao2009-09-281-2/+6
| | | | | | | | | | | | | | | | For async direct IO that covers holes or fallocate, the end_io callback function now queued the convertion work on workqueue but don't flush the work rightaway as it might take too long to afford. But when fsync is called after all the data is completed, user expects the metadata also being updated before fsync returns. Thus we need to flush the conversion work when fsync() is called. This patch keep track of a listed of completed async direct io that has a work queued on workqueue. When fsync() is called, it will go through the list and do the conversion. Signed-off-by: Mingming Cao <cmm@us.ibm.com>
* ext4: Use end_io callback to avoid direct I/O fallback to buffered I/OMingming Cao2009-09-281-0/+11
| | | | | | | | | | | | | | | | | | | | | Currently the DIO VFS code passes create = 0 when writing to the middle of file. It does this to avoid block allocation for holes, so as not to expose stale data out when there is a parallel buffered read (which does not hold the i_mutex lock). Direct I/O writes into holes falls back to buffered IO for this reason. Since preallocated extents are treated as holes when doing a get_block() look up (buffer is not mapped), direct IO over fallocate also falls back to buffered IO. Thus ext4 actually silently falls back to buffered IO in above two cases, which is undesirable. To fix this, this patch creates unitialized extents when a direct I/O write into holes in sparse files, and registering an end_io callback which converts the uninitialized extent to an initialized extent after the I/O is completed. Singed-Off-By: Mingming Cao <cmm@us.ibm.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* ext4: Adjust ext4_da_writepages() to write out larger contiguous chunksTheodore Ts'o2009-09-291-0/+3
| | | | | | | | | | | | | | Work around problems in the writeback code to force out writebacks in larger chunks than just 4mb, which is just too small. This also works around limitations in the ext4 block allocator, which can't allocate more than 2048 blocks at a time. So we need to defeat the round-robin characteristics of the writeback code and try to write out as many blocks in one inode before allowing the writeback code to move on to another inode. We add a a new per-filesystem tunable, max_writeback_mb_bump, which caps this to a default of 128mb per inode. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* const: make struct super_block::s_qcop constAlexey Dobriyan2009-09-221-1/+1
| | | | | | Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* const: make struct super_block::dq_op constAlexey Dobriyan2009-09-221-1/+1
| | | | | | Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ext4: limit block allocations for indirect-block files to < 2^32Eric Sandeen2009-09-161-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Today, the ext4 allocator will happily allocate blocks past 2^32 for indirect-block files, which results in the block numbers getting truncated, and corruption ensues. This patch limits such allocations to < 2^32, and adds BUG_ONs if we do get blocks larger than that. This should address RH Bug 519471, ext4 bitmap allocator must limit blocks to < 2^32 * ext4_find_goal() is modified to choose a goal < UINT_MAX, so that our starting point is in an acceptable range. * ext4_xattr_block_set() is modified such that the goal block is < UINT_MAX, as above. * ext4_mb_regular_allocator() is modified so that the group search does not continue into groups which are too high * ext4_mb_use_preallocated() has a check that we don't use preallocated space which is too far out * ext4_alloc_blocks() and ext4_xattr_block_set() add some BUG_ONs No attempt has been made to limit inode locations to < 2^32, so we may wind up with blocks far from their inodes. Doing this much already will lead to some odd ENOSPC issues when the "lower 32" gets full, and further restricting inodes could make that even weirder. For high inodes, choosing a goal of the original, % UINT_MAX, may be a bit odd, but then we're in an odd situation anyway, and I don't know of a better heuristic. Signed-off-by: Eric Sandeen <sandeen@redhat.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* ext4: Fix include/trace/events/ext4.h to work with SystemtapTheodore Ts'o2009-09-141-0/+1
| | | | | | | | | | | | | Using relative pathnames in #include statements interacts badly with SystemTap, since the fs/ext4/*.h header files are not packaged up as part of a distribution kernel's header files. Since systemtap doesn't use TP_fast_assign(), we can use a blind structure definition and then make sure the needed header files are defined before the ext4 source files #include the trace/events/ext4.h header file. https://bugzilla.redhat.com/show_bug.cgi?id=512478 Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* ext4: Fix initalization of s_flex_groupsTheodore Ts'o2009-09-111-6/+6
| | | | | | | | | | | | | | The s_flex_groups array should have been initialized using atomic_add to sum up the free counts from the block groups that make up a flex_bg. By using atomic_set, the value of the s_flex_groups array was set to the values of the last block group in the flex_bg. The impact of this bug is that the block and inode allocation algorithms might not pick the best flex_bg for new allocation. Thanks to Damien Guibouret for pointing out this problem! Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* ext4: Don't update superblock write time when filesystem is read-onlyTheodore Ts'o2009-09-101-1/+12
| | | | | | | | | | | This avoids updating the superblock write time when we are mounting the root file system read/only but we need to replay the journal; at that point, for people who are east of GMT and who make their clock tick in localtime for Windows bug-for-bug compatibility, and this will cause e2fsck to complain and force a full file system check. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* ext4: Remove journal_checksum mount option and enable it by defaultTheodore Ts'o2009-09-051-14/+6
| | | | | | | | | There's no real cost for the journal checksum feature, and we should make sure it is enabled all the time. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* ext4: Add feature set check helper for mount & remount pathsEric Sandeen2009-08-181-42/+49
| | | | | | | | | | | | | | | | | | | | | A user reported that although his root ext4 filesystem was mounting fine, other filesystems would not mount, with the: "Filesystem with huge files cannot be mounted RDWR without CONFIG_LBDAF" error on his 32-bit box built without CONFIG_LBDAF. This is because the test at mount time for this situation was not being re-checked on remount, and the normal boot process makes an ro->rw transition, so this was being missed. Refactor to make a common helper function to test the filesystem features against the type of mount request (RO vs. RW) so that we stay consistent. Addresses Red-Hat-Bugzilla: #517650 Signed-off-by: Eric Sandeen <sandeen@redhat.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* ext4: reject too-large filesystems on 32-bit kernelsEric Sandeen2009-08-171-3/+10
| | | | | | | | | | | | | | | ext4 will happily mount a > 16T filesystem on a 32-bit box, but this is not safe; writes to the block device will wrap past 16T and the page cache can't index past 16T (232 index * 4k pages). Adding another test to the existing "too many sectors" test should do the trick. Add a comment, a relevant return value, and fix the reference to the CONFIG_LBD(AF) option as well. Signed-off-by: Eric Sandeen <sandeen@redhat.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* ext4: Avoid null pointer dereference when decoding EROFS w/o a journalTheodore Ts'o2009-07-271-1/+2
| | | | | | | | We need to check to make sure a journal is present before checking the journal flags in ext4_decode_error(). Signed-off-by: Eric Sesterhenn <eric.sesterhenn@lsexperts.de> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* switch ext4 to inode->i_aclAl Viro2009-06-241-16/+0
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-blockLinus Torvalds2009-06-191-5/+5
|\ | | | | | | | | | | | | | | * 'for-linus' of git://git.kernel.dk/linux-2.6-block: Fix kernel-doc parameter name typo in blk-settings.c: block: rename CONFIG_LBD to CONFIG_LBDAF block: Fix bounce_pfn setting hd: stop defining MAJOR_NR
| * block: rename CONFIG_LBD to CONFIG_LBDAFBartlomiej Zolnierkiewicz2009-06-191-5/+5
| | | | | | | | | | | | | | | | | | | | | | | | Follow-up to "block: enable by default support for large devices and files on 32-bit archs". Rename CONFIG_LBD to CONFIG_LBDAF to: - allow update of existing [def]configs for "default y" change - reflect that it is used also for large files support nowadays Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* | ext4: teach the inode allocator to use a goal inode numberAndreas Dilger2009-06-131-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Enhance the inode allocator to take a goal inode number as a paremeter; if it is specified, it takes precedence over Orlov or parent directory inode allocation algorithms. The extents migration function uses the goal inode number so that the extent trees allocated the migration function use the correct flex_bg. In the future, the goal inode functionality will also be used to allocate an adjacent inode for the extended attributes. Also, for testing purposes the goal inode number can be specified via /sys/fs/{dev}/inode_goal. This can be useful for testing inode allocation beyond 2^32 blocks on very large filesystems. Signed-off-by: Andreas Dilger <adilger@sun.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* | ext4: move the abort flag from s_mount_opts to s_mount_flagsTheodore Ts'o2009-06-131-5/+5
| | | | | | | | | | | | | | | | | | | | | | We're running out of space in the mount options word, and EXT4_MOUNT_ABORT isn't really a mount option, but a run-time flag. So move it to become EXT4_MF_FS_ABORTED in s_mount_flags. Also remove bogus ext2_fs.h / ext4.h simultaneous #include protection, which can never happen. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* | ext4: change s_mount_opt to be an unsigned intTheodore Ts'o2009-06-131-1/+1
| | | | | | | | | | | | | | | | We can only fit 32 options in s_mount_opt because an unsigned long is 32-bits on a x86 machine. So use an unsigned int to save space on 64-bit platforms. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* | ext4: convert instrumentation from markers to tracepointsTheodore Ts'o2009-06-171-2/+4
|/ | | | Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* Push BKL down into ->remount_fs()Alessio Igor Bogani2009-06-111-0/+4
| | | | | | | [xfs, btrfs, capifs, shmem don't need BKL, exempt] Signed-off-by: Alessio Igor Bogani <abogani@texware.it> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* ->write_super lock_super pushdownChristoph Hellwig2009-06-111-1/+3
| | | | | | | | | | | | | | | | | | | Push down lock_super into ->write_super instances and remove it from the caller. Following filesystem don't need ->s_lock in ->write_super and are skipped: * bfs, nilfs2 - no other uses of s_lock and have internal locks in ->write_super * ext2 - uses BKL in ext2_write_super and has internal calls without s_lock * reiserfs - no other uses of s_lock as has reiserfs_write_lock (BKL) in ->write_super * xfs - no other uses of s_lock and uses internal lock (buffer lock on superblock buffer) to serialize ->write_super. Also xfs_fs_write_super is superflous and will go away in the next merge window Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Push lock_super() into the ->remount_fs() of filesystems that care about itAl Viro2009-06-111-0/+3
| | | | | | | | | | | | | Note that since we can't run into contention between remount_fs and write_super (due to exclusion on s_umount), we have to care only about filesystems that touch lock_super() on their own. Out of those ext3, ext4, hpfs, sysv and ufs do need it; fat doesn't since its ->remount_fs() only accesses assign-once data (basically, it's "we have no atime on directories and only have atime on files for vfat; force nodiratime and possibly noatime into *flags"). [folded a build fix from hch] Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* push BKL down into ->put_superChristoph Hellwig2009-06-111-1/+1
| | | | | | | | | | | | | | | | | Move BKL into ->put_super from the only caller. A couple of filesystems had trivial enough ->put_super (only kfree and NULLing of s_fs_info + stuff in there) to not get any locking: coda, cramfs, efs, hugetlbfs, omfs, qnx4, shmem, all others got the full treatment. Most of them probably don't need it, but I'd rather sort that out individually. Preferably after all the other BKL pushdowns in that area. [AV: original used to move lock_super() down as well; these changes are removed since we don't do lock_super() at all in generic_shutdown_super() now] [AV: fuse, btrfs and xfs are known to need no damn BKL, exempt] Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* No need to do lock_super() for exclusion in generic_shutdown_super()Al Viro2009-06-111-1/+1
| | | | | | | | | | | | | | We can't run into contention on it. All other callers of lock_super() either hold s_umount (and we have it exclusive) or hold an active reference to superblock in question, which prevents the call of generic_shutdown_super() while the reference is held. So we can replace lock_super(s) with get_fs_excl() in generic_shutdown_super() (and corresponding change for unlock_super(), of course). Since ext4 expects s_lock held for its put_super, take lock_super() into it. The rest of filesystems do not care at all. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* remove ->write_super call in generic_shutdown_superChristoph Hellwig2009-06-111-0/+3
| | | | | | | | | | | | | | | | | | | | | We just did a full fs writeout using sync_filesystem before, and if that's not enough for the filesystem it can perform it's own writeout in ->put_super, which many filesystems already do. Move a call to foofs_write_super into every foofs_put_super for now to guarantee identical behaviour until it's cleaned up by the individual filesystem maintainers. Exceptions: - affs already has identical copy & pasted code at the beginning of affs_put_super so no need to do it twice. - xfs does the right thing without it and I have changes pending for the xfs tree touching this are so I don't really need conflicts here.. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Merge branch 'for-2.6.31' of git://git.kernel.dk/linux-2.6-blockLinus Torvalds2009-06-111-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * 'for-2.6.31' of git://git.kernel.dk/linux-2.6-block: (153 commits) block: add request clone interface (v2) floppy: fix hibernation ramdisk: remove long-deprecated "ramdisk=" boot-time parameter fs/bio.c: add missing __user annotation block: prevent possible io_context->refcount overflow Add serial number support for virtio_blk, V4a block: Add missing bounce_pfn stacking and fix comments Revert "block: Fix bounce limit setting in DM" cciss: decode unit attention in SCSI error handling code cciss: Remove no longer needed sendcmd reject processing code cciss: change SCSI error handling routines to work with interrupts enabled. cciss: separate error processing and command retrying code in sendcmd_withirq_core() cciss: factor out fix target status processing code from sendcmd functions cciss: simplify interface of sendcmd() and sendcmd_withirq() cciss: factor out core of sendcmd_withirq() for use by SCSI error handling code cciss: Use schedule_timeout_uninterruptible in SCSI error handling code block: needs to set the residual length of a bidi request Revert "block: implement blkdev_readpages" block: Fix bounce limit setting in DM Removed reference to non-existing file Documentation/PCI/PCI-DMA-mapping.txt ... Manually fix conflicts with tracing updates in: block/blk-sysfs.c drivers/ide/ide-atapi.c drivers/ide/ide-cd.c drivers/ide/ide-floppy.c drivers/ide/ide-tape.c include/trace/events/block.h kernel/trace/blktrace.c
| * block: Do away with the notion of hardsect_sizeMartin K. Petersen2009-05-221-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Until now we have had a 1:1 mapping between storage device physical block size and the logical block sized used when addressing the device. With SATA 4KB drives coming out that will no longer be the case. The sector size will be 4KB but the logical block size will remain 512-bytes. Hence we need to distinguish between the physical block size and the logical ditto. This patch renames hardsect_size to logical_block_size. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* | ext4: Change all super.c messages to print the deviceEric Sandeen2009-06-041-229/+233
| | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch changes ext4 super.c to include the device name with all warning/error messages, by using a new utility function ext4_msg. It's a rather large patch, but very mechanic. I left debug printks alone. This is a straightforward port of a patch which Andi Kleen did for ext3. Cc: Andi Kleen <ak@linux.intel.com> Signed-off-by: Eric Sandeen <sandeen@redhat.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* | ext4: super.c whitespace cleanupAndreas Dilger2009-06-031-56/+61
| | | | | | | | | | | | | | | | | | | | Cleanup of whitespace and formatting. Initially driven by confusing indents for the ext4_{block,inode}_bitmap() et. al. helper routines, but figured I'd cleanup some other 80-column wrapping and other indenting problems at the same time. Signed-off-by: Andreas Dilger <adilger@sun.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* | ext4: Clean up calls to ext4_get_group_desc()Theodore Ts'o2009-05-251-2/+1
| | | | | | | | | | | | | | | | If the caller isn't planning on modifying the block group descriptors, there's no need to pass in a pointer to a struct buffer_head. Nuking this saves a tiny amount of CPU time and stack space usage. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* | ext4: Fix memory leak in ext4_fill_super() in case of a failed mountManish Katiyar2009-05-171-0/+1
| | | | | | | | | | Signed-off-by: Manish Katiyar <mkatiyar@gmail.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* | ext4: Add a comprehensive block validity check to ext4_get_blocks()Theodore Ts'o2009-05-171-2/+30
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | To catch filesystem bugs or corruption which could lead to the filesystem getting severly damaged, this patch adds a facility for tracking all of the filesystem metadata blocks by contiguous regions in a red-black tree. This allows quick searching of the tree to locate extents which might overlap with filesystem metadata blocks. This facility is also used by the multi-block allocator to assure that it is not allocating blocks out of the system zone, as well as by the routines used when reading indirect blocks and extents information from disk to make sure their contents are valid. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* | ext4: Convert ext4_lock_group to use sb_bgl_lockAneesh Kumar K.V2009-05-021-3/+3
| | | | | | | | | | | | | | | | | | | | | | We have sb_bgl_lock() and ext4_group_info.bb_state bit spinlock to protech group information. The later is only used within mballoc code. Consolidate them to use sb_bgl_lock(). This makes the mballoc.c code much simpler and also avoid confusion with two locks protecting same info. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* | ext4: Make the length of the mb_history file tunableCurt Wohlgemuth2009-05-011-1/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In memory-constrained systems with many partitions, the ~68K for each partition for the mb_history buffer can be excessive. This patch adds a new mount option, mb_history_length, as well as a way of setting the default via a module parameter (or via a sysfs parameter in /sys/module/ext4/parameter/default_mb_history_length). If the mb_history_length is set to zero, the mb_history facility is disabled entirely. Signed-off-by: Curt Wohlgemuth <curtw@google.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* | ext4: Move fs/ext4/group.h into ext4.hTheodore Ts'o2009-05-011-1/+0
| | | | | | | | | | | | | | Move the function prototypes in group.h into ext4.h so they are all defined in one place. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* | ext4: Move fs/ext4/namei.h into ext4.hTheodore Ts'o2009-05-011-1/+0
| | | | | | | | | | | | | | | | The fs/ext4/namei.h header file had only a single function declaration, and should have never been a standalone file. Move it into ext4.h, where should have been from the beginning. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* | ext4: Replace lock/unlock_super() with an explicit lock for resizingTheodore Ts'o2009-04-251-0/+1
| | | | | | | | | | | | | | | | | | Use a separate lock to protect s_groups_count and the other block group descriptors which get changed via an on-line resize operation, so we can stop overloading the use of lock_super(). Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* | ext4: Replace lock/unlock_super() with an explicit lock for the orphan listTheodore Ts'o2009-04-251-0/+1
| | | | | | | | | | | | | | Use a separate lock to protect the orphan list, so we can stop overloading the use of lock_super(). Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* | ext4: ext4_mark_recovery_complete() doesn't need to use lock_superTheodore Ts'o2009-05-011-10/+1
| | | | | | | | | | | | | | | | | | | | | | | | The function ext4_mark_recovery_complete() is called from two call paths: either (a) while mounting the filesystem, in which case there's no danger of any other CPU calling write_super() until the mount is completed, and (b) while remounting the filesystem read-write, in which case the fs core has already locked the superblock. This also allows us to take out a very vile unlock_super()/lock_super() pair in ext4_remount(). Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* | ext4: Remove outdated comment about lock_super()Theodore Ts'o2009-04-251-8/+0
| | | | | | | | | | | | | | | | | | ext4_fill_super() is no longer called by read_super(), and it is no longer called with the superblock locked. The unlock_super()/lock_super() is no longer present, so this comment is entirely superfluous. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* | ext4: Avoid races caused by on-line resizing and SMP memory reorderingTheodore Ts'o2009-05-011-2/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Ext4's on-line resizing adds a new block group and then, only at the last step adjusts s_groups_count. However, it's possible on SMP systems that another CPU could see the updated the s_group_count and not see the newly initialized data structures for the just-added block group. For this reason, it's important to insert a SMP read barrier after reading s_groups_count and before reading any (for example) the new block group descriptors allowed by the increased value of s_groups_count. Unfortunately, we rather blatently violate this locking protocol documented in fs/ext4/resize.c. Fortunately, (1) on-line resizes happen relatively rarely, and (2) it seems rare that the filesystem code will immediately try to use just-added block group before any memory ordering issues resolve themselves. So apparently problems here are relatively hard to hit, since ext3 has been vulnerable to the same issue for years with no one apparently complaining. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* | ext4: Use separate super_operations structure for no_journal filesystemsTheodore Ts'o2009-05-011-51/+57
| | | | | | | | | | | | | | | | | | | | By using a separate super_operations structure for filesystems that have and don't have journals, we can simply ext4_write_super() --- which is only needed when no journal is present --- and ext4_freeze(), ext4_unfreeze(), and ext4_sync_fs(), which are only needed when the journal is present. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* | ext4: Fix and simplify s_dirt handlingTheodore Ts'o2009-04-301-11/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The s_dirt flag wasn't completely handled correctly, but it didn't really matter when journalling was enabled. It turns out that when ext4 runs without a journal, we don't clear s_dirt in places where we should have, with the result that the high-level write_super() function was writing the superblock when it wasn't necessary. So we fix this by making ext4_commit_super() clear the s_dirt flag, and removing many of the other places where s_dirt is manipulated. When journalling is enabled, the s_dirt flag might be left set more often, but s_dirt really doesn't matter when journalling is enabled. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* | ext4: Simplify ext4_commit_super()'s function signatureTheodore Ts'o2009-05-011-17/+16
| | | | | | | | | | | | | | | | The ext4_commit_super() function took both a struct super_block * and a struct ext4_super_block *, but the struct ext4_super_block can be derived from the struct super_block. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* | ext4: Use is_power_of_2() for clarityTheodore Ts'o2009-04-241-3/+2
| | | | | | | | | | Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
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