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authorDavide Italiano <dccitaliano@gmail.com>2015-09-16 17:36:23 +0300
committerJiri Slaby <jslaby@suse.cz>2015-09-18 09:26:31 +0200
commit7e7ec82ecd66ed0cfd77346d8cb4676e06b881ec (patch)
tree079b1098fa07160962b820d9fdc0edcb36e51c86
parentbf9adcbe5206ddd199d7447f1d79729a7980dbdd (diff)
downloadlwn-7e7ec82ecd66ed0cfd77346d8cb4676e06b881ec.tar.gz
lwn-7e7ec82ecd66ed0cfd77346d8cb4676e06b881ec.zip
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. [Nikolay Borisov: Bakported to 3.12.47 - Adjusted context - Add the 'out' label] Signed-off-by: Davide Italiano <dccitaliano@gmail.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Nikolay Borisov <kernel@kyup.com> Cc: Jan Kara <jack@suse.cz> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
-rw-r--r--fs/ext4/extents.c17
1 files changed, 11 insertions, 6 deletions
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index c9830686cbd5..a9d23daa0d6f 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -4634,12 +4634,6 @@ long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
if (ret)
return ret;
- /*
- * currently supporting (pre)allocate mode for extent-based
- * files _only_
- */
- if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
- return -EOPNOTSUPP;
trace_ext4_fallocate_enter(inode, offset, len, mode);
map.m_lblk = offset >> blkbits;
@@ -4654,6 +4648,16 @@ 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);
+
+ /*
+ * currently supporting (pre)allocate mode 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);
@@ -4714,6 +4718,7 @@ retry:
ret = 0;
goto retry;
}
+out:
mutex_unlock(&inode->i_mutex);
trace_ext4_fallocate_exit(inode, offset, max_blocks,
ret > 0 ? ret2 : ret);