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authorTheodore Ts'o <tytso@mit.edu>2021-08-21 06:44:17 +0300
committerTheodore Ts'o <tytso@mit.edu>2021-08-31 06:36:50 +0300
commita54c4613dac1500b40e4ab55199f7c51f028e848 (patch)
treebc30df927da83ea3ac12345fcea64f104e6b8230 /fs
parentb33d9f5909c8d30f1429fb9aefbb32760901a023 (diff)
downloadlinux-a54c4613dac1500b40e4ab55199f7c51f028e848.tar.xz
ext4: fix race writing to an inline_data file while its xattrs are changing
The location of the system.data extended attribute can change whenever xattr_sem is not taken. So we need to recalculate the i_inline_off field since it mgiht have changed between ext4_write_begin() and ext4_write_end(). This means that caching i_inline_off is probably not helpful, so in the long run we should probably get rid of it and shrink the in-memory ext4 inode slightly, but let's fix the race the simple way for now. Cc: stable@kernel.org Fixes: f19d5870cbf72 ("ext4: add normal write support for inline data") Reported-by: syzbot+13146364637c7363a7de@syzkaller.appspotmail.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs')
-rw-r--r--fs/ext4/inline.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c
index 70cb64db33f7..24e994e75f5c 100644
--- a/fs/ext4/inline.c
+++ b/fs/ext4/inline.c
@@ -750,6 +750,12 @@ int ext4_write_inline_data_end(struct inode *inode, loff_t pos, unsigned len,
ext4_write_lock_xattr(inode, &no_expand);
BUG_ON(!ext4_has_inline_data(inode));
+ /*
+ * ei->i_inline_off may have changed since ext4_write_begin()
+ * called ext4_try_to_write_inline_data()
+ */
+ (void) ext4_find_inline_data_nolock(inode);
+
kaddr = kmap_atomic(page);
ext4_write_inline_data(inode, &iloc, kaddr, pos, len);
kunmap_atomic(kaddr);