| From | lizf@kernel ... | Subject | [PATCH 3.4 069/146] ext4: move check under lock scope to close a race. | Date | Tue, 15 Sep 2015 17:03:04 +0800 |
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From: Davide Italiano <dccitaliano@gmail.com>
3.4.109-rc1 review patch. If anyone has any objections, please let me know.
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commit 280227a75b56ab5d35854f3a77ef74a7ad56a203 upstream.
fallocate() checks that the file is extent-based and returns EOPNOTSUPP in case is not. Other tasks can convert from and to indirect and extent so it's safe to check only after grabbing the inode mutex.
Signed-off-by: Davide Italiano <dccitaliano@gmail.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> [lizf: Backported to 3.4: - adjust context - return -EOPNOTSUPP instead of jumping to the "out" label] Signed-off-by: Zefan Li <lizefan@huawei.com> --- fs/ext4/extents.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-)
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index 4296a6f..bb72833 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -4365,13 +4365,6 @@ long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len) struct ext4_map_blocks map; unsigned int credits, blkbits = inode->i_blkbits; - /* - * currently supporting (pre)allocate mode for extent-based - * files _only_ - */ - if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) - return -EOPNOTSUPP; - /* Return error if mode is not supported */ if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE)) return -EOPNOTSUPP; @@ -4392,6 +4385,15 @@ long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len) */ credits = ext4_chunk_trans_blocks(inode, max_blocks); mutex_lock(&inode->i_mutex); + + /* + * We only support preallocation for extent-based files only + */ + if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) { + mutex_unlock(&inode->i_mutex); + return -EOPNOTSUPP; + } + ret = inode_newsize_ok(inode, (len + offset)); if (ret) { mutex_unlock(&inode->i_mutex); -- 1.9.1
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