From: Sougata Santra <[email protected]> 3.12-stable review patch. If anyone has any objections, please let me know.
=============== commit d7bdb996aef67ea24c62707ca4e29b07025e9683 upstream. 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. [[email protected]: take extents_lock before taking a copy of ->alloc_blocks] [[email protected]: remove now-unused label `out'] Signed-off-by: Sougata Santra <[email protected]> Reviewed-by: Christoph Hellwig <[email protected]> Cc: Vyacheslav Dubeyko <[email protected]> Cc: Alexey Khoroshilov <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> Signed-off-by: Jiri Slaby <[email protected]> --- fs/hfsplus/extents.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/fs/hfsplus/extents.c b/fs/hfsplus/extents.c index fbb212fbb1ef..f0f601c83ad6 100644 --- a/fs/hfsplus/extents.c +++ b/fs/hfsplus/extents.c @@ -498,11 +498,13 @@ 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: @@ -556,11 +558,13 @@ 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); @@ -592,10 +596,10 @@ 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; -- 2.1.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
