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| author | Eryu Guan <guaneryu@gmail.com> | 2013-02-22 20:27:47 (GMT) |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2013-02-22 20:27:47 (GMT) |
| commit | d43814721111041e26671a153e300e2054fb36fa (patch) | |
| tree | cf9fd202aca4cae83989000219921ac99134f557 | |
| parent | 1231b3a1eb5740192aeebf5344dd6d6da000febf (diff) | |
| download | linux-d43814721111041e26671a153e300e2054fb36fa.tar.xz | |
ext4: no need to remove extent if len is 0 in ext4_es_remove_extent()
len is 0 means no extent needs to be removed, so return immediately.
Otherwise it could trigger the following BUG_ON() in
ext4_es_remove_extent()
end = lblk + len - 1;
BUG_ON(end < lblk);
This could be reproduced by a simple truncate(1) command by an
unprivileged user
truncate -s $(($((2**32 - 1)) * 4096)) /mnt/ext4/testfile
The same is true for __es_insert_extent().
Patched kernel passed xfstests regression test.
Signed-off-by: Eryu Guan <guaneryu@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>
| -rw-r--r-- | fs/ext4/extents_status.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/fs/ext4/extents_status.c b/fs/ext4/extents_status.c index 9f1380e..f768f4a 100644 --- a/fs/ext4/extents_status.c +++ b/fs/ext4/extents_status.c @@ -456,6 +456,9 @@ int ext4_es_insert_extent(struct inode *inode, ext4_lblk_t lblk, es_debug("add [%u/%u) %llu %llx to extent status tree of inode %lu\n", lblk, len, pblk, status, inode->i_ino); + if (!len) + return 0; + BUG_ON(end < lblk); newes.es_lblk = lblk; @@ -649,6 +652,9 @@ int ext4_es_remove_extent(struct inode *inode, ext4_lblk_t lblk, es_debug("remove [%u/%u) from extent status tree of inode %lu\n", lblk, len, inode->i_ino); + if (!len) + return err; + end = lblk + len - 1; BUG_ON(end < lblk); |