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authorTheodore Ts'o <tytso@mit.edu>2018-12-25 00:56:33 -0500
committerTheodore Ts'o <tytso@mit.edu>2018-12-25 00:56:33 -0500
commit2b08b1f12cd664dc7d5c84ead9ff25ae97ad5491 (patch)
treeec4e19afec1556c8aeecef9a460a1208c1a71c83 /fs/ext4/inline.c
parent812c0cab2c0dfad977605dbadf9148490ca5d93f (diff)
downloadlinux-stericsson-2b08b1f12cd664dc7d5c84ead9ff25ae97ad5491.tar.gz
ext4: fix a potential fiemap/page fault deadlock w/ inline_data
The ext4_inline_data_fiemap() function calls fiemap_fill_next_extent() while still holding the xattr semaphore. This is not necessary and it triggers a circular lockdep warning. This is because fiemap_fill_next_extent() could trigger a page fault when it writes into page which triggers a page fault. If that page is mmaped from the inline file in question, this could very well result in a deadlock. This problem can be reproduced using generic/519 with a file system configuration which has the inline_data feature enabled. Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@kernel.org
Diffstat (limited to 'fs/ext4/inline.c')
-rw-r--r--fs/ext4/inline.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c
index 27373d88b5f0..56f6e1782d5f 100644
--- a/fs/ext4/inline.c
+++ b/fs/ext4/inline.c
@@ -1890,12 +1890,12 @@ int ext4_inline_data_fiemap(struct inode *inode,
physical += (char *)ext4_raw_inode(&iloc) - iloc.bh->b_data;
physical += offsetof(struct ext4_inode, i_block);
- if (physical)
- error = fiemap_fill_next_extent(fieinfo, start, physical,
- inline_len, flags);
brelse(iloc.bh);
out:
up_read(&EXT4_I(inode)->xattr_sem);
+ if (physical)
+ error = fiemap_fill_next_extent(fieinfo, start, physical,
+ inline_len, flags);
return (error < 0 ? error : 0);
}