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| author | Jan Kara <jack@suse.cz> | 2016-08-11 12:38:55 -0400 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2016-08-11 12:38:55 -0400 |
| commit | 2e81a4eeedcaa66e35f58b81e0755b87057ce392 (patch) | |
| tree | c51fa9b5eb8a39ec51afcaf836b2a7ad597743cd /fs/ext4 | |
| parent | 443a8c41cd49de66a3fda45b32b9860ea0292b84 (diff) | |
| download | linux-2e81a4eeedcaa66e35f58b81e0755b87057ce392.tar.gz linux-2e81a4eeedcaa66e35f58b81e0755b87057ce392.tar.bz2 linux-2e81a4eeedcaa66e35f58b81e0755b87057ce392.zip | |
ext4: avoid deadlock when expanding inode size
When we need to move xattrs into external xattr block, we call
ext4_xattr_block_set() from ext4_expand_extra_isize_ea(). That may end
up calling ext4_mark_inode_dirty() again which will recurse back into
the inode expansion code leading to deadlocks.
Protect from recursion using EXT4_STATE_NO_EXPAND inode flag and move
its management into ext4_expand_extra_isize_ea() since its manipulation
is safe there (due to xattr_sem) from possible races with
ext4_xattr_set_handle() which plays with it as well.
CC: stable@vger.kernel.org # 4.4.x
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs/ext4')
| -rw-r--r-- | fs/ext4/inode.c | 2 | ||||
| -rw-r--r-- | fs/ext4/xattr.c | 19 |
2 files changed, 13 insertions, 8 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 5a6277d80f7c..13c95b290263 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -5466,8 +5466,6 @@ int ext4_mark_inode_dirty(handle_t *handle, struct inode *inode) sbi->s_want_extra_isize, iloc, handle); if (ret) { - ext4_set_inode_state(inode, - EXT4_STATE_NO_EXPAND); if (mnt_count != le16_to_cpu(sbi->s_es->s_mnt_count)) { ext4_warning(inode->i_sb, diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c index c893f00b6dc0..2eb935ca5d9e 100644 --- a/fs/ext4/xattr.c +++ b/fs/ext4/xattr.c @@ -1358,12 +1358,14 @@ int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize, int isize_diff; /* How much do we need to grow i_extra_isize */ down_write(&EXT4_I(inode)->xattr_sem); + /* + * Set EXT4_STATE_NO_EXPAND to avoid recursion when marking inode dirty + */ + ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND); retry: isize_diff = new_extra_isize - EXT4_I(inode)->i_extra_isize; - if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) { - up_write(&EXT4_I(inode)->xattr_sem); - return 0; - } + if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) + goto out; header = IHDR(inode, raw_inode); entry = IFIRST(header); @@ -1392,8 +1394,7 @@ retry: (void *)header, total_ino, inode->i_sb->s_blocksize); EXT4_I(inode)->i_extra_isize = new_extra_isize; - error = 0; - goto cleanup; + goto out; } /* @@ -1553,6 +1554,8 @@ retry: kfree(bs); } brelse(bh); +out: + ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND); up_write(&EXT4_I(inode)->xattr_sem); return 0; @@ -1564,6 +1567,10 @@ cleanup: kfree(is); kfree(bs); brelse(bh); + /* + * We deliberately leave EXT4_STATE_NO_EXPAND set here since inode + * size expansion failed. + */ up_write(&EXT4_I(inode)->xattr_sem); return error; } |