From f82b735936ffd58b6711cf1f1054616517d8ffcd Mon Sep 17 00:00:00 2001 From: Liu Bo Date: Mon, 23 Oct 2017 23:18:16 -0600 Subject: Btrfs: add write_flags for compression bio Compression code path has only flaged bios with REQ_OP_WRITE no matter where the bios come from, but it could be a sync write if fsync starts this writeback or a normal writeback write if wb kthread starts a periodic writeback. It breaks the rule that sync writes and writeback writes need to be differentiated from each other, because from the POV of block layer, all bios need to be recognized by these flags in order to do some management, e.g. throttlling. This passes writeback_control to compression write path so that it can send bios with proper flags to block layer. Signed-off-by: Liu Bo Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/compression.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'fs/btrfs/compression.c') diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c index b35ce16b3df3..4a78e5726337 100644 --- a/fs/btrfs/compression.c +++ b/fs/btrfs/compression.c @@ -295,7 +295,8 @@ blk_status_t btrfs_submit_compressed_write(struct inode *inode, u64 start, unsigned long len, u64 disk_start, unsigned long compressed_len, struct page **compressed_pages, - unsigned long nr_pages) + unsigned long nr_pages, + unsigned int write_flags) { struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); struct bio *bio = NULL; @@ -327,7 +328,7 @@ blk_status_t btrfs_submit_compressed_write(struct inode *inode, u64 start, bdev = fs_info->fs_devices->latest_bdev; bio = btrfs_bio_alloc(bdev, first_byte); - bio_set_op_attrs(bio, REQ_OP_WRITE, 0); + bio->bi_opf = REQ_OP_WRITE | write_flags; bio->bi_private = cb; bio->bi_end_io = end_compressed_bio_write; refcount_set(&cb->pending_bios, 1); @@ -374,7 +375,7 @@ blk_status_t btrfs_submit_compressed_write(struct inode *inode, u64 start, bio_put(bio); bio = btrfs_bio_alloc(bdev, first_byte); - bio_set_op_attrs(bio, REQ_OP_WRITE, 0); + bio->bi_opf = REQ_OP_WRITE | write_flags; bio->bi_private = cb; bio->bi_end_io = end_compressed_bio_write; bio_add_page(bio, page, PAGE_SIZE, 0); -- cgit v1.2.3 From eae8d82529dd9820e206ecba0047b806c4410e65 Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Mon, 6 Nov 2017 10:43:18 +0800 Subject: btrfs: Fix wild memory access in compression level parser [BUG] Kernel panic when mounting with "-o compress" mount option. KASAN will report like: ------ ================================================================== BUG: KASAN: wild-memory-access in strncmp+0x31/0xc0 Read of size 1 at addr d86735fce994f800 by task mount/662 ... Call Trace: dump_stack+0xe3/0x175 kasan_report+0x163/0x370 __asan_load1+0x47/0x50 strncmp+0x31/0xc0 btrfs_compress_str2level+0x20/0x70 [btrfs] btrfs_parse_options+0xff4/0x1870 [btrfs] open_ctree+0x2679/0x49f0 [btrfs] btrfs_mount+0x1b7f/0x1d30 [btrfs] mount_fs+0x49/0x190 vfs_kern_mount.part.29+0xba/0x280 vfs_kern_mount+0x13/0x20 btrfs_mount+0x31e/0x1d30 [btrfs] mount_fs+0x49/0x190 vfs_kern_mount.part.29+0xba/0x280 do_mount+0xaad/0x1a00 SyS_mount+0x98/0xe0 entry_SYSCALL_64_fastpath+0x1f/0xbe ------ [Cause] For 'compress' and 'compress_force' options, its token doesn't expect any parameter so its args[0] contains uninitialized data. Accessing args[0] will cause above wild memory access. [Fix] For Opt_compress and Opt_compress_force, set compression level to the default. Signed-off-by: Qu Wenruo Reviewed-by: David Sterba [ set the default in advance ] Signed-off-by: David Sterba --- fs/btrfs/compression.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs/btrfs/compression.c') diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c index 4a78e5726337..5982c8a71f02 100644 --- a/fs/btrfs/compression.c +++ b/fs/btrfs/compression.c @@ -1529,5 +1529,5 @@ unsigned int btrfs_compress_str2level(const char *str) if (str[4] == ':' && '1' <= str[5] && str[5] <= '9' && str[6] == 0) return str[5] - '0'; - return 0; + return BTRFS_ZLIB_DEFAULT_LEVEL; } -- cgit v1.2.3