From de134cb54c3a67644ff95b1c9bffe545e752c912 Mon Sep 17 00:00:00 2001 From: Boris Burkov Date: Wed, 20 Aug 2025 14:52:05 -0700 Subject: btrfs: fix squota compressed stats leak The following workload on a squota enabled fs: btrfs subvol create mnt/subvol # ensure subvol extents get accounted sync btrfs qgroup create 1/1 mnt btrfs qgroup assign mnt/subvol 1/1 mnt btrfs qgroup delete mnt/subvol # make the cleaner thread run btrfs filesystem sync mnt sleep 1 btrfs filesystem sync mnt btrfs qgroup destroy 1/1 mnt will fail with EBUSY. The reason is that 1/1 does the quick accounting when we assign subvol to it, gaining its exclusive usage as excl and excl_cmpr. But then when we delete subvol, the decrement happens via record_squota_delta() which does not update excl_cmpr, as squotas does not make any distinction between compressed and normal extents. Thus, we increment excl_cmpr but never decrement it, and are unable to delete 1/1. The two possible fixes are to make squota always mirror excl and excl_cmpr or to make the fast accounting separately track the plain and cmpr numbers. The latter felt cleaner to me so that is what I opted for. Fixes: 1e0e9d5771c3 ("btrfs: add helper for recording simple quota deltas") CC: stable@vger.kernel.org # 6.12+ Reviewed-by: Qu Wenruo Signed-off-by: Boris Burkov Signed-off-by: David Sterba --- fs/btrfs/qgroup.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'fs') diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c index ccaa9a3cf1ce..da102da169fd 100644 --- a/fs/btrfs/qgroup.c +++ b/fs/btrfs/qgroup.c @@ -1455,6 +1455,7 @@ static int __qgroup_excl_accounting(struct btrfs_fs_info *fs_info, u64 ref_root, struct btrfs_qgroup *qgroup; LIST_HEAD(qgroup_list); u64 num_bytes = src->excl; + u64 num_bytes_cmpr = src->excl_cmpr; int ret = 0; qgroup = find_qgroup_rb(fs_info, ref_root); @@ -1466,11 +1467,12 @@ static int __qgroup_excl_accounting(struct btrfs_fs_info *fs_info, u64 ref_root, struct btrfs_qgroup_list *glist; qgroup->rfer += sign * num_bytes; - qgroup->rfer_cmpr += sign * num_bytes; + qgroup->rfer_cmpr += sign * num_bytes_cmpr; WARN_ON(sign < 0 && qgroup->excl < num_bytes); + WARN_ON(sign < 0 && qgroup->excl_cmpr < num_bytes_cmpr); qgroup->excl += sign * num_bytes; - qgroup->excl_cmpr += sign * num_bytes; + qgroup->excl_cmpr += sign * num_bytes_cmpr; if (sign > 0) qgroup_rsv_add_by_qgroup(fs_info, qgroup, src); -- cgit v1.2.3 From 6db1df415d73fcad12134a54f97dc6c8a64ab181 Mon Sep 17 00:00:00 2001 From: Calvin Owens Date: Mon, 25 Aug 2025 18:32:04 +0930 Subject: btrfs: accept and ignore compression level for lzo The compression level is meaningless for lzo, but before commit 3f093ccb95f30 ("btrfs: harden parsing of compression mount options"), it was silently ignored if passed. After that commit, passing a level with lzo fails to mount: BTRFS error: unrecognized compression value lzo:1 It seems reasonable for users to expect that lzo would permit a numeric level option, as all the other algos do, even though the kernel's implementation of LZO currently only supports a single level. Because it has always worked to pass a level, it seems likely to me that users in the real world are relying on doing so. This patch restores the old behavior, giving "lzo:N" the same semantics as all of the other compression algos. To be clear, silly variants like "lzo:one", "lzo:the_first_option", or "lzo:armageddon" also used to work. This isn't meant to suggest that any possible mis-interpretation of mount options that once worked must continue to work forever. This is an exceptional case where it makes sense to preserve compatibility, both because the mis-interpretation is reasonable, and because nothing tangible is sacrificed. Finally update btrfs_show_options() to ignore the level of LZO, as it is only the default level without any extra meaning. Fixes: 3f093ccb95f30 ("btrfs: harden parsing of compression mount options") Reviewed-by: Daniel Vacek Reviewed-by: Qu Wenruo Signed-off-by: Calvin Owens Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/super.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) (limited to 'fs') diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index 7f31f8bd63ba..e708faf1892f 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -299,9 +299,12 @@ static int btrfs_parse_compress(struct btrfs_fs_context *ctx, btrfs_set_opt(ctx->mount_opt, COMPRESS); btrfs_clear_opt(ctx->mount_opt, NODATACOW); btrfs_clear_opt(ctx->mount_opt, NODATASUM); - } else if (btrfs_match_compress_type(string, "lzo", false)) { + } else if (btrfs_match_compress_type(string, "lzo", true)) { ctx->compress_type = BTRFS_COMPRESS_LZO; - ctx->compress_level = 0; + ctx->compress_level = btrfs_compress_str2level(BTRFS_COMPRESS_LZO, + string + 3); + if (string[3] == ':' && string[4]) + btrfs_warn(NULL, "Compression level ignored for LZO"); btrfs_set_opt(ctx->mount_opt, COMPRESS); btrfs_clear_opt(ctx->mount_opt, NODATACOW); btrfs_clear_opt(ctx->mount_opt, NODATASUM); @@ -1079,7 +1082,7 @@ static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry) seq_printf(seq, ",compress-force=%s", compress_type); else seq_printf(seq, ",compress=%s", compress_type); - if (info->compress_level) + if (info->compress_level && info->compress_type != BTRFS_COMPRESS_LZO) seq_printf(seq, ":%d", info->compress_level); } if (btrfs_test_opt(info, NOSSD)) -- cgit v1.2.3 From 9786531399a679fc2f4630d2c0a186205282ab2f Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Fri, 22 Aug 2025 16:06:13 +0930 Subject: btrfs: fix corruption reading compressed range when block size is smaller than page size [BUG] With 64K page size (aarch64 with 64K page size config) and 4K btrfs block size, the following workload can easily lead to a corrupted read: mkfs.btrfs -f -s 4k $dev > /dev/null mount -o compress $dev $mnt xfs_io -f -c "pwrite -S 0xff 0 64k" $mnt/base > /dev/null echo "correct result:" od -Ad -t x1 $mnt/base xfs_io -f -c "reflink $mnt/base 32k 0 32k" \ -c "reflink $mnt/base 0 32k 32k" \ -c "pwrite -S 0xff 60k 4k" $mnt/new > /dev/null echo "incorrect result:" od -Ad -t x1 $mnt/new umount $mnt This shows the following result: correct result: 0000000 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff * 0065536 incorrect result: 0000000 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff * 0032768 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 * 0061440 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff * 0065536 Notice the zero in the range [32K, 60K), which is incorrect. [CAUSE] With extra trace printk, it shows the following events during od: (some unrelated info removed like CPU and context) od-3457 btrfs_do_readpage: enter r/i=5/258 folio=0(65536) prev_em_start=0000000000000000 The "r/i" is indicating the root and inode number. In our case the file "new" is using ino 258 from fs tree (root 5). Here notice the @prev_em_start pointer is NULL. This means the btrfs_do_readpage() is called from btrfs_read_folio(), not from btrfs_readahead(). od-3457 btrfs_do_readpage: r/i=5/258 folio=0(65536) cur=0 got em start=0 len=32768 od-3457 btrfs_do_readpage: r/i=5/258 folio=0(65536) cur=4096 got em start=0 len=32768 od-3457 btrfs_do_readpage: r/i=5/258 folio=0(65536) cur=8192 got em start=0 len=32768 od-3457 btrfs_do_readpage: r/i=5/258 folio=0(65536) cur=12288 got em start=0 len=32768 od-3457 btrfs_do_readpage: r/i=5/258 folio=0(65536) cur=16384 got em start=0 len=32768 od-3457 btrfs_do_readpage: r/i=5/258 folio=0(65536) cur=20480 got em start=0 len=32768 od-3457 btrfs_do_readpage: r/i=5/258 folio=0(65536) cur=24576 got em start=0 len=32768 od-3457 btrfs_do_readpage: r/i=5/258 folio=0(65536) cur=28672 got em start=0 len=32768 These above 32K blocks will be read from the first half of the compressed data extent. od-3457 btrfs_do_readpage: r/i=5/258 folio=0(65536) cur=32768 got em start=32768 len=32768 Note here there is no btrfs_submit_compressed_read() call. Which is incorrect now. Although both extent maps at 0 and 32K are pointing to the same compressed data, their offsets are different thus can not be merged into the same read. So this means the compressed data read merge check is doing something wrong. od-3457 btrfs_do_readpage: r/i=5/258 folio=0(65536) cur=36864 got em start=32768 len=32768 od-3457 btrfs_do_readpage: r/i=5/258 folio=0(65536) cur=40960 got em start=32768 len=32768 od-3457 btrfs_do_readpage: r/i=5/258 folio=0(65536) cur=45056 got em start=32768 len=32768 od-3457 btrfs_do_readpage: r/i=5/258 folio=0(65536) cur=49152 got em start=32768 len=32768 od-3457 btrfs_do_readpage: r/i=5/258 folio=0(65536) cur=53248 got em start=32768 len=32768 od-3457 btrfs_do_readpage: r/i=5/258 folio=0(65536) cur=57344 got em start=32768 len=32768 od-3457 btrfs_do_readpage: r/i=5/258 folio=0(65536) cur=61440 skip uptodate od-3457 btrfs_submit_compressed_read: cb orig_bio: file off=0 len=61440 The function btrfs_submit_compressed_read() is only called at the end of folio read. The compressed bio will only have an extent map of range [0, 32K), but the original bio passed in is for the whole 64K folio. This will cause the decompression part to only fill the first 32K, leaving the rest untouched (aka, filled with zero). This incorrect compressed read merge leads to the above data corruption. There were similar problems that happened in the past, commit 808f80b46790 ("Btrfs: update fix for read corruption of compressed and shared extents") is doing pretty much the same fix for readahead. But that's back to 2015, where btrfs still only supports bs (block size) == ps (page size) cases. This means btrfs_do_readpage() only needs to handle a folio which contains exactly one block. Only btrfs_readahead() can lead to a read covering multiple blocks. Thus only btrfs_readahead() passes a non-NULL @prev_em_start pointer. With v5.15 kernel btrfs introduced bs < ps support. This breaks the above assumption that a folio can only contain one block. Now btrfs_read_folio() can also read multiple blocks in one go. But btrfs_read_folio() doesn't pass a @prev_em_start pointer, thus the existing bio force submission check will never be triggered. In theory, this can also happen for btrfs with large folios, but since large folio is still experimental, we don't need to bother it, thus only bs < ps support is affected for now. [FIX] Instead of passing @prev_em_start to do the proper compressed extent check, introduce one new member, btrfs_bio_ctrl::last_em_start, so that the existing bio force submission logic will always be triggered. CC: stable@vger.kernel.org # 5.15+ Reviewed-by: Filipe Manana Signed-off-by: Qu Wenruo Signed-off-by: David Sterba --- fs/btrfs/extent_io.c | 40 ++++++++++++++++++++++++++++++---------- 1 file changed, 30 insertions(+), 10 deletions(-) (limited to 'fs') diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index c953297aa89a..b21cb72835cc 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -111,6 +111,24 @@ struct btrfs_bio_ctrl { */ unsigned long submit_bitmap; struct readahead_control *ractl; + + /* + * The start offset of the last used extent map by a read operation. + * + * This is for proper compressed read merge. + * U64_MAX means we are starting the read and have made no progress yet. + * + * The current btrfs_bio_is_contig() only uses disk_bytenr as + * the condition to check if the read can be merged with previous + * bio, which is not correct. E.g. two file extents pointing to the + * same extent but with different offset. + * + * So here we need to do extra checks to only merge reads that are + * covered by the same extent map. + * Just extent_map::start will be enough, as they are unique + * inside the same inode. + */ + u64 last_em_start; }; static void submit_one_bio(struct btrfs_bio_ctrl *bio_ctrl) @@ -909,7 +927,7 @@ static void btrfs_readahead_expand(struct readahead_control *ractl, * return 0 on success, otherwise return error */ static int btrfs_do_readpage(struct folio *folio, struct extent_map **em_cached, - struct btrfs_bio_ctrl *bio_ctrl, u64 *prev_em_start) + struct btrfs_bio_ctrl *bio_ctrl) { struct inode *inode = folio->mapping->host; struct btrfs_fs_info *fs_info = inode_to_fs_info(inode); @@ -1019,12 +1037,11 @@ static int btrfs_do_readpage(struct folio *folio, struct extent_map **em_cached, * non-optimal behavior (submitting 2 bios for the same extent). */ if (compress_type != BTRFS_COMPRESS_NONE && - prev_em_start && *prev_em_start != (u64)-1 && - *prev_em_start != em->start) + bio_ctrl->last_em_start != U64_MAX && + bio_ctrl->last_em_start != em->start) force_bio_submit = true; - if (prev_em_start) - *prev_em_start = em->start; + bio_ctrl->last_em_start = em->start; btrfs_free_extent_map(em); em = NULL; @@ -1238,12 +1255,15 @@ int btrfs_read_folio(struct file *file, struct folio *folio) const u64 start = folio_pos(folio); const u64 end = start + folio_size(folio) - 1; struct extent_state *cached_state = NULL; - struct btrfs_bio_ctrl bio_ctrl = { .opf = REQ_OP_READ }; + struct btrfs_bio_ctrl bio_ctrl = { + .opf = REQ_OP_READ, + .last_em_start = U64_MAX, + }; struct extent_map *em_cached = NULL; int ret; lock_extents_for_read(inode, start, end, &cached_state); - ret = btrfs_do_readpage(folio, &em_cached, &bio_ctrl, NULL); + ret = btrfs_do_readpage(folio, &em_cached, &bio_ctrl); btrfs_unlock_extent(&inode->io_tree, start, end, &cached_state); btrfs_free_extent_map(em_cached); @@ -2583,7 +2603,8 @@ void btrfs_readahead(struct readahead_control *rac) { struct btrfs_bio_ctrl bio_ctrl = { .opf = REQ_OP_READ | REQ_RAHEAD, - .ractl = rac + .ractl = rac, + .last_em_start = U64_MAX, }; struct folio *folio; struct btrfs_inode *inode = BTRFS_I(rac->mapping->host); @@ -2591,12 +2612,11 @@ void btrfs_readahead(struct readahead_control *rac) const u64 end = start + readahead_length(rac) - 1; struct extent_state *cached_state = NULL; struct extent_map *em_cached = NULL; - u64 prev_em_start = (u64)-1; lock_extents_for_read(inode, start, end, &cached_state); while ((folio = readahead_folio(rac)) != NULL) - btrfs_do_readpage(folio, &em_cached, &bio_ctrl, &prev_em_start); + btrfs_do_readpage(folio, &em_cached, &bio_ctrl); btrfs_unlock_extent(&inode->io_tree, start, end, &cached_state); -- cgit v1.2.3 From f6a6c280059c4ddc23e12e3de1b01098e240036f Mon Sep 17 00:00:00 2001 From: Omar Sandoval Date: Tue, 26 Aug 2025 11:24:38 -0700 Subject: btrfs: fix subvolume deletion lockup caused by inodes xarray race There is a race condition between inode eviction and inode caching that can cause a live struct btrfs_inode to be missing from the root->inodes xarray. Specifically, there is a window during evict() between the inode being unhashed and deleted from the xarray. If btrfs_iget() is called for the same inode in that window, it will be recreated and inserted into the xarray, but then eviction will delete the new entry, leaving nothing in the xarray: Thread 1 Thread 2 --------------------------------------------------------------- evict() remove_inode_hash() btrfs_iget_path() btrfs_iget_locked() btrfs_read_locked_inode() btrfs_add_inode_to_root() destroy_inode() btrfs_destroy_inode() btrfs_del_inode_from_root() __xa_erase In turn, this can cause issues for subvolume deletion. Specifically, if an inode is in this lost state, and all other inodes are evicted, then btrfs_del_inode_from_root() will call btrfs_add_dead_root() prematurely. If the lost inode has a delayed_node attached to it, then when btrfs_clean_one_deleted_snapshot() calls btrfs_kill_all_delayed_nodes(), it will loop forever because the delayed_nodes xarray will never become empty (unless memory pressure forces the inode out). We saw this manifest as soft lockups in production. Fix it by only deleting the xarray entry if it matches the given inode (using __xa_cmpxchg()). Fixes: 310b2f5d5a94 ("btrfs: use an xarray to track open inodes in a root") Cc: stable@vger.kernel.org # 6.11+ Reviewed-by: Josef Bacik Reviewed-by: Filipe Manana Co-authored-by: Leo Martins Signed-off-by: Leo Martins Signed-off-by: Omar Sandoval Signed-off-by: David Sterba --- fs/btrfs/inode.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) (limited to 'fs') diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index dd82dcc7b2b7..e7218e78bff4 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -5696,7 +5696,17 @@ static void btrfs_del_inode_from_root(struct btrfs_inode *inode) bool empty = false; xa_lock(&root->inodes); - entry = __xa_erase(&root->inodes, btrfs_ino(inode)); + /* + * This btrfs_inode is being freed and has already been unhashed at this + * point. It's possible that another btrfs_inode has already been + * allocated for the same inode and inserted itself into the root, so + * don't delete it in that case. + * + * Note that this shouldn't need to allocate memory, so the gfp flags + * don't really matter. + */ + entry = __xa_cmpxchg(&root->inodes, btrfs_ino(inode), inode, NULL, + GFP_ATOMIC); if (entry == inode) empty = xa_empty(&root->inodes); xa_unlock(&root->inodes); -- cgit v1.2.3 From 3d1267475b94b3df7a61e4ea6788c7c5d9e473c4 Mon Sep 17 00:00:00 2001 From: Mark Harmstone Date: Tue, 2 Sep 2025 11:34:10 +0100 Subject: btrfs: don't allow adding block device of less than 1 MB Commit 15ae0410c37a79 ("btrfs-progs: add error handling for device_get_partition_size_fd_stat()") in btrfs-progs inadvertently changed it so that if the BLKGETSIZE64 ioctl on a block device returned a size of 0, this was no longer seen as an error condition. Unfortunately this is how disconnected NBD devices behave, meaning that with btrfs-progs 6.16 it's now possible to add a device you can't remove: # btrfs device add /dev/nbd0 /root/temp # btrfs device remove /dev/nbd0 /root/temp ERROR: error removing device '/dev/nbd0': Invalid argument This check should always have been done kernel-side anyway, so add a check in btrfs_init_new_device() that the new device doesn't have a size less than BTRFS_DEVICE_RANGE_RESERVED (i.e. 1 MB). Reviewed-by: Qu Wenruo Signed-off-by: Mark Harmstone Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/volumes.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'fs') diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index fa7a929a0461..c6e3efd6f602 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -2722,6 +2722,11 @@ int btrfs_init_new_device(struct btrfs_fs_info *fs_info, const char *device_path goto error; } + if (bdev_nr_bytes(file_bdev(bdev_file)) <= BTRFS_DEVICE_RANGE_RESERVED) { + ret = -EINVAL; + goto error; + } + if (fs_devices->seeding) { seeding_dev = true; down_write(&sb->s_umount); -- cgit v1.2.3