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btrfs: convert compressed_bio.pending_bios from atomic_t to refcount_t 

refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.

Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Elena Reshetova 2017-03-03 10:55:20 +02:00 committed by David Sterba
parent b7ac31b7b2
commit a50299ae7c
1 changed files with 9 additions and 9 deletions
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18
fs/btrfs/compression.c
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@ -44,7 +44,7 @@
struct compressed_bio {
/* number of bios pending for this compressed extent */
atomic_t pending_bios;
refcount_t pending_bios;
/* the pages with the compressed data on them */
struct page **compressed_pages;
@ -161,7 +161,7 @@ static void end_compressed_bio_read(struct bio *bio)
/* if there are more bios still pending for this compressed
* extent, just exit
*/
if (!atomic_dec_and_test(&cb->pending_bios))
if (!refcount_dec_and_test(&cb->pending_bios))
goto out;
inode = cb->inode;
@ -274,7 +274,7 @@ static void end_compressed_bio_write(struct bio *bio)
/* if there are more bios still pending for this compressed
* extent, just exit
*/
if (!atomic_dec_and_test(&cb->pending_bios))
if (!refcount_dec_and_test(&cb->pending_bios))
goto out;
/* ok, we're the last bio for this extent, step one is to
@ -342,7 +342,7 @@ int btrfs_submit_compressed_write(struct inode *inode, u64 start,
cb = kmalloc(compressed_bio_size(fs_info, compressed_len), GFP_NOFS);
if (!cb)
return -ENOMEM;
atomic_set(&cb->pending_bios, 0);
refcount_set(&cb->pending_bios, 0);
cb->errors = 0;
cb->inode = inode;
cb->start = start;
@ -363,7 +363,7 @@ int btrfs_submit_compressed_write(struct inode *inode, u64 start,
bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
bio->bi_private = cb;
bio->bi_end_io = end_compressed_bio_write;
atomic_inc(&cb->pending_bios);
refcount_set(&cb->pending_bios, 1);
/* create and submit bios for the compressed pages */
bytes_left = compressed_len;
@ -388,7 +388,7 @@ int btrfs_submit_compressed_write(struct inode *inode, u64 start,
* we inc the count. Otherwise, the cb might get
* freed before we're done setting it up
*/
atomic_inc(&cb->pending_bios);
refcount_inc(&cb->pending_bios);
ret = btrfs_bio_wq_end_io(fs_info, bio,
BTRFS_WQ_ENDIO_DATA);
BUG_ON(ret); /* -ENOMEM */
@ -607,7 +607,7 @@ int btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
if (!cb)
goto out;
atomic_set(&cb->pending_bios, 0);
refcount_set(&cb->pending_bios, 0);
cb->errors = 0;
cb->inode = inode;
cb->mirror_num = mirror_num;
@ -656,7 +656,7 @@ int btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
bio_set_op_attrs (comp_bio, REQ_OP_READ, 0);
comp_bio->bi_private = cb;
comp_bio->bi_end_io = end_compressed_bio_read;
atomic_inc(&cb->pending_bios);
refcount_set(&cb->pending_bios, 1);
for (pg_index = 0; pg_index < nr_pages; pg_index++) {
page = cb->compressed_pages[pg_index];
@ -685,7 +685,7 @@ int btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
* we inc the count. Otherwise, the cb might get
* freed before we're done setting it up
*/
atomic_inc(&cb->pending_bios);
refcount_inc(&cb->pending_bios);
if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) {
ret = btrfs_lookup_bio_sums(inode, comp_bio,