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authorSougata Santra <sougata@tuxera.com>2014-04-03 14:50:34 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-04-03 16:21:26 -0700
commitd7bdb996aef67ea24c62707ca4e29b07025e9683 (patch)
tree619189c603f5ff8dca0f83880bc38382da61039d
parentabfeb724b43f371ea70ec2c1290ed33e6f65db60 (diff)
downloadlinux-linaro-stable-d7bdb996aef67ea24c62707ca4e29b07025e9683.tar.gz
fs/hfsplus/extents.c: fix concurrent acess of alloc_blocks
Concurrent access to alloc_blocks in hfsplus_inode_info() is protected by extents_lock mutex. This patch fixes two instances where alloc_blocks modification was not protected with this lock. This fixes possible allocation bitmap corruption in race conditions while extending and truncating files. [akpm@linux-foundation.org: take extents_lock before taking a copy of ->alloc_blocks] [akpm@linux-foundation.org: remove now-unused label `out'] Signed-off-by: Sougata Santra <sougata@tuxera.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Vyacheslav Dubeyko <slava@dubeyko.com> Cc: Alexey Khoroshilov <khoroshilov@ispras.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/hfsplus/extents.c14
1 files changed, 9 insertions, 5 deletions
diff --git a/fs/hfsplus/extents.c b/fs/hfsplus/extents.c
index 136d860cd746..a7aafb35b624 100644
--- a/fs/hfsplus/extents.c
+++ b/fs/hfsplus/extents.c
@@ -496,11 +496,13 @@ int hfsplus_file_extend(struct inode *inode)
goto insert_extent;
}
out:
- mutex_unlock(&hip->extents_lock);
if (!res) {
hip->alloc_blocks += len;
+ mutex_unlock(&hip->extents_lock);
hfsplus_mark_inode_dirty(inode, HFSPLUS_I_ALLOC_DIRTY);
+ return 0;
}
+ mutex_unlock(&hip->extents_lock);
return res;
insert_extent:
@@ -554,11 +556,13 @@ void hfsplus_file_truncate(struct inode *inode)
blk_cnt = (inode->i_size + HFSPLUS_SB(sb)->alloc_blksz - 1) >>
HFSPLUS_SB(sb)->alloc_blksz_shift;
+
+ mutex_lock(&hip->extents_lock);
+
alloc_cnt = hip->alloc_blocks;
if (blk_cnt == alloc_cnt)
- goto out;
+ goto out_unlock;
- mutex_lock(&hip->extents_lock);
res = hfs_find_init(HFSPLUS_SB(sb)->ext_tree, &fd);
if (res) {
mutex_unlock(&hip->extents_lock);
@@ -590,10 +594,10 @@ void hfsplus_file_truncate(struct inode *inode)
hfs_brec_remove(&fd);
}
hfs_find_exit(&fd);
- mutex_unlock(&hip->extents_lock);
hip->alloc_blocks = blk_cnt;
-out:
+out_unlock:
+ mutex_unlock(&hip->extents_lock);
hip->phys_size = inode->i_size;
hip->fs_blocks = (inode->i_size + sb->s_blocksize - 1) >>
sb->s_blocksize_bits;