From 4209178b876408926ef6f02e51dd447bcebde977 Mon Sep 17 00:00:00 2001 From: Davide Italiano Date: Sat, 2 May 2015 23:21:15 -0400 Subject: [PATCH] ext4: move check under lock scope to close a race. 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 Signed-off-by: Theodore Ts'o [bwh: Backported to 3.2: - Adjust context - Add the 'out' label] Signed-off-by: Ben Hutchings --- fs/ext4/extents.c | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index 834d9a19e379..0eed964f696e 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -4470,13 +4470,6 @@ 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; @@ -4497,6 +4490,15 @@ 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))) { + ret = -EOPNOTSUPP; + goto out; + } + ret = inode_newsize_ok(inode, (len + offset)); if (ret) { mutex_unlock(&inode->i_mutex); @@ -4553,6 +4555,7 @@ retry: ret = 0; goto retry; } +out: mutex_unlock(&inode->i_mutex); trace_ext4_fallocate_exit(inode, offset, max_blocks, ret > 0 ? ret2 : ret); -- 2.39.2