diff options
| author | Xiyu Yang | 2021-07-19 13:59:14 +0800 |
|---|---|---|
| committer | Theodore Ts'o | 2021-11-04 10:33:24 -0400 |
| commit | 31d21d219b51dcfb16e18427eddae5394d402820 (patch) | |
| tree | 15aedfa14e985faefebd636c0869a63c08c9473e | |
| parent | 1811bc401aa58c7bdb0df3205aa6613b49d32127 (diff) | |
ext4: convert from atomic_t to refcount_t on ext4_io_end->count
refcount_t type and corresponding API can protect refcounters from
accidental underflow and overflow and further use-after-free situations.
Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/1626674355-55795-1-git-send-email-xiyuyang19@fudan.edu.cn
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
| -rw-r--r-- | fs/ext4/ext4.h | 3 | ||||
| -rw-r--r-- | fs/ext4/page-io.c | 8 |
2 files changed, 6 insertions, 5 deletions
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 3825195539d7..404dd50856e5 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -17,6 +17,7 @@ #ifndef _EXT4_H #define _EXT4_H +#include <linux/refcount.h> #include <linux/types.h> #include <linux/blkdev.h> #include <linux/magic.h> @@ -241,7 +242,7 @@ typedef struct ext4_io_end { struct bio *bio; /* Linked list of completed * bios covering the extent */ unsigned int flag; /* unwritten or not */ - atomic_t count; /* reference counter */ + refcount_t count; /* reference counter */ struct list_head list_vec; /* list of ext4_io_end_vec */ } ext4_io_end_t; diff --git a/fs/ext4/page-io.c b/fs/ext4/page-io.c index f038d578d8d8..9cb261714991 100644 --- a/fs/ext4/page-io.c +++ b/fs/ext4/page-io.c @@ -279,14 +279,14 @@ ext4_io_end_t *ext4_init_io_end(struct inode *inode, gfp_t flags) io_end->inode = inode; INIT_LIST_HEAD(&io_end->list); INIT_LIST_HEAD(&io_end->list_vec); - atomic_set(&io_end->count, 1); + refcount_set(&io_end->count, 1); } return io_end; } void ext4_put_io_end_defer(ext4_io_end_t *io_end) { - if (atomic_dec_and_test(&io_end->count)) { + if (refcount_dec_and_test(&io_end->count)) { if (!(io_end->flag & EXT4_IO_END_UNWRITTEN) || list_empty(&io_end->list_vec)) { ext4_release_io_end(io_end); @@ -300,7 +300,7 @@ int ext4_put_io_end(ext4_io_end_t *io_end) { int err = 0; - if (atomic_dec_and_test(&io_end->count)) { + if (refcount_dec_and_test(&io_end->count)) { if (io_end->flag & EXT4_IO_END_UNWRITTEN) { err = ext4_convert_unwritten_io_end_vec(io_end->handle, io_end); @@ -314,7 +314,7 @@ int ext4_put_io_end(ext4_io_end_t *io_end) ext4_io_end_t *ext4_get_io_end(ext4_io_end_t *io_end) { - atomic_inc(&io_end->count); + refcount_inc(&io_end->count); return io_end; } |