FAILED: patch "[PATCH] btrfs: fix ssd_spread overallocation" failed to apply to 6.6-stable tree
The patch below does not apply to the 6.6-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y git checkout FETCH_HEAD git cherry-pick -x 807d9023e75fc20bfd6dd2ac0408ce4af53f1648 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2025081832-unearned-monopoly-13b1@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 807d9023e75fc20bfd6dd2ac0408ce4af53f1648 Mon Sep 17 00:00:00 2001 From: Boris Burkov boris@bur.io Date: Mon, 14 Jul 2025 16:44:28 -0700 Subject: [PATCH] btrfs: fix ssd_spread overallocation
If the ssd_spread mount option is enabled, then we run the so called clustered allocator for data block groups. In practice, this results in creating a btrfs_free_cluster which caches a block_group and borrows its free extents for allocation.
Since the introduction of allocation size classes in 6.1, there has been a bug in the interaction between that feature and ssd_spread. find_free_extent() has a number of nested loops. The loop going over the allocation stages, stored in ffe_ctl->loop and managed by find_free_extent_update_loop(), the loop over the raid levels, and the loop over all the block_groups in a space_info. The size class feature relies on the block_group loop to ensure it gets a chance to see a block_group of a given size class. However, the clustered allocator uses the cached cluster block_group and breaks that loop. Each call to do_allocation() will really just go back to the same cached block_group. Normally, this is OK, as the allocation either succeeds and we don't want to loop any more or it fails, and we clear the cluster and return its space to the block_group.
But with size classes, the allocation can succeed, then later fail, outside of do_allocation() due to size class mismatch. That latter failure is not properly handled due to the highly complex multi loop logic. The result is a painful loop where we continue to allocate the same num_bytes from the cluster in a tight loop until it fails and releases the cluster and lets us try a new block_group. But by then, we have skipped great swaths of the available block_groups and are likely to fail to allocate, looping the outer loop. In pathological cases like the reproducer below, the cached block_group is often the very last one, in which case we don't perform this tight bg loop but instead rip through the ffe stages to LOOP_CHUNK_ALLOC and allocate a chunk, which is now the last one, and we enter the tight inner loop until an allocation failure. Then allocation succeeds on the final block_group and if the next allocation is a size mismatch, the exact same thing happens again.
Triggering this is as easy as mounting with -o ssd_spread and then running:
mount -o ssd_spread $dev $mnt dd if=/dev/zero of=$mnt/big bs=16M count=1 &>/dev/null dd if=/dev/zero of=$mnt/med bs=4M count=1 &>/dev/null sync
if you do the two writes + sync in a loop, you can force btrfs to spin an excessive amount on semi-successful clustered allocations, before ultimately failing and advancing to the stage where we force a chunk allocation. This results in 2G of data allocated per iteration, despite only using ~20M of data. By using a small size classed extent, the inner loop takes longer and we can spin for longer.
The simplest, shortest term fix to unbreak this is to make the clustered allocator size_class aware in the dumbest way, where it fails on size class mismatch. This may hinder the operation of the clustered allocator, but better hindered than completely broken and terribly overallocating.
Further re-design improvements are also in the works.
Fixes: 52bb7a2166af ("btrfs: introduce size class to block group allocator") CC: stable@vger.kernel.org # 6.1+ Reported-by: David Sterba dsterba@suse.com Reviewed-by: Filipe Manana fdmanana@suse.com Signed-off-by: Boris Burkov boris@bur.io Signed-off-by: David Sterba dsterba@suse.com
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 85833bf216de..97d517cdf2df 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -3651,6 +3651,21 @@ btrfs_release_block_group(struct btrfs_block_group *cache, btrfs_put_block_group(cache); }
+static bool find_free_extent_check_size_class(const struct find_free_extent_ctl *ffe_ctl, + const struct btrfs_block_group *bg) +{ + if (ffe_ctl->policy == BTRFS_EXTENT_ALLOC_ZONED) + return true; + if (!btrfs_block_group_should_use_size_class(bg)) + return true; + if (ffe_ctl->loop >= LOOP_WRONG_SIZE_CLASS) + return true; + if (ffe_ctl->loop >= LOOP_UNSET_SIZE_CLASS && + bg->size_class == BTRFS_BG_SZ_NONE) + return true; + return ffe_ctl->size_class == bg->size_class; +} + /* * Helper function for find_free_extent(). * @@ -3672,7 +3687,8 @@ static int find_free_extent_clustered(struct btrfs_block_group *bg, if (!cluster_bg) goto refill_cluster; if (cluster_bg != bg && (cluster_bg->ro || - !block_group_bits(cluster_bg, ffe_ctl->flags))) + !block_group_bits(cluster_bg, ffe_ctl->flags) || + !find_free_extent_check_size_class(ffe_ctl, cluster_bg))) goto release_cluster;
offset = btrfs_alloc_from_cluster(cluster_bg, last_ptr, @@ -4229,21 +4245,6 @@ static int find_free_extent_update_loop(struct btrfs_fs_info *fs_info, return -ENOSPC; }
-static bool find_free_extent_check_size_class(struct find_free_extent_ctl *ffe_ctl, - struct btrfs_block_group *bg) -{ - if (ffe_ctl->policy == BTRFS_EXTENT_ALLOC_ZONED) - return true; - if (!btrfs_block_group_should_use_size_class(bg)) - return true; - if (ffe_ctl->loop >= LOOP_WRONG_SIZE_CLASS) - return true; - if (ffe_ctl->loop >= LOOP_UNSET_SIZE_CLASS && - bg->size_class == BTRFS_BG_SZ_NONE) - return true; - return ffe_ctl->size_class == bg->size_class; -} - static int prepare_allocation_clustered(struct btrfs_fs_info *fs_info, struct find_free_extent_ctl *ffe_ctl, struct btrfs_space_info *space_info,
From: Boris Burkov boris@bur.io
[ Upstream commit 807d9023e75fc20bfd6dd2ac0408ce4af53f1648 ]
If the ssd_spread mount option is enabled, then we run the so called clustered allocator for data block groups. In practice, this results in creating a btrfs_free_cluster which caches a block_group and borrows its free extents for allocation.
Since the introduction of allocation size classes in 6.1, there has been a bug in the interaction between that feature and ssd_spread. find_free_extent() has a number of nested loops. The loop going over the allocation stages, stored in ffe_ctl->loop and managed by find_free_extent_update_loop(), the loop over the raid levels, and the loop over all the block_groups in a space_info. The size class feature relies on the block_group loop to ensure it gets a chance to see a block_group of a given size class. However, the clustered allocator uses the cached cluster block_group and breaks that loop. Each call to do_allocation() will really just go back to the same cached block_group. Normally, this is OK, as the allocation either succeeds and we don't want to loop any more or it fails, and we clear the cluster and return its space to the block_group.
But with size classes, the allocation can succeed, then later fail, outside of do_allocation() due to size class mismatch. That latter failure is not properly handled due to the highly complex multi loop logic. The result is a painful loop where we continue to allocate the same num_bytes from the cluster in a tight loop until it fails and releases the cluster and lets us try a new block_group. But by then, we have skipped great swaths of the available block_groups and are likely to fail to allocate, looping the outer loop. In pathological cases like the reproducer below, the cached block_group is often the very last one, in which case we don't perform this tight bg loop but instead rip through the ffe stages to LOOP_CHUNK_ALLOC and allocate a chunk, which is now the last one, and we enter the tight inner loop until an allocation failure. Then allocation succeeds on the final block_group and if the next allocation is a size mismatch, the exact same thing happens again.
Triggering this is as easy as mounting with -o ssd_spread and then running:
mount -o ssd_spread $dev $mnt dd if=/dev/zero of=$mnt/big bs=16M count=1 &>/dev/null dd if=/dev/zero of=$mnt/med bs=4M count=1 &>/dev/null sync
if you do the two writes + sync in a loop, you can force btrfs to spin an excessive amount on semi-successful clustered allocations, before ultimately failing and advancing to the stage where we force a chunk allocation. This results in 2G of data allocated per iteration, despite only using ~20M of data. By using a small size classed extent, the inner loop takes longer and we can spin for longer.
The simplest, shortest term fix to unbreak this is to make the clustered allocator size_class aware in the dumbest way, where it fails on size class mismatch. This may hinder the operation of the clustered allocator, but better hindered than completely broken and terribly overallocating.
Further re-design improvements are also in the works.
Fixes: 52bb7a2166af ("btrfs: introduce size class to block group allocator") CC: stable@vger.kernel.org # 6.1+ Reported-by: David Sterba dsterba@suse.com Reviewed-by: Filipe Manana fdmanana@suse.com Signed-off-by: Boris Burkov boris@bur.io Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/btrfs/extent-tree.c | 33 +++++++++++++++++---------------- 1 file changed, 17 insertions(+), 16 deletions(-)
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index ef77d4208510..8248113eb067 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -3530,6 +3530,21 @@ btrfs_release_block_group(struct btrfs_block_group *cache, btrfs_put_block_group(cache); }
+static bool find_free_extent_check_size_class(const struct find_free_extent_ctl *ffe_ctl, + const struct btrfs_block_group *bg) +{ + if (ffe_ctl->policy == BTRFS_EXTENT_ALLOC_ZONED) + return true; + if (!btrfs_block_group_should_use_size_class(bg)) + return true; + if (ffe_ctl->loop >= LOOP_WRONG_SIZE_CLASS) + return true; + if (ffe_ctl->loop >= LOOP_UNSET_SIZE_CLASS && + bg->size_class == BTRFS_BG_SZ_NONE) + return true; + return ffe_ctl->size_class == bg->size_class; +} + /* * Helper function for find_free_extent(). * @@ -3551,7 +3566,8 @@ static int find_free_extent_clustered(struct btrfs_block_group *bg, if (!cluster_bg) goto refill_cluster; if (cluster_bg != bg && (cluster_bg->ro || - !block_group_bits(cluster_bg, ffe_ctl->flags))) + !block_group_bits(cluster_bg, ffe_ctl->flags) || + !find_free_extent_check_size_class(ffe_ctl, cluster_bg))) goto release_cluster;
offset = btrfs_alloc_from_cluster(cluster_bg, last_ptr, @@ -4107,21 +4123,6 @@ static int find_free_extent_update_loop(struct btrfs_fs_info *fs_info, return -ENOSPC; }
-static bool find_free_extent_check_size_class(struct find_free_extent_ctl *ffe_ctl, - struct btrfs_block_group *bg) -{ - if (ffe_ctl->policy == BTRFS_EXTENT_ALLOC_ZONED) - return true; - if (!btrfs_block_group_should_use_size_class(bg)) - return true; - if (ffe_ctl->loop >= LOOP_WRONG_SIZE_CLASS) - return true; - if (ffe_ctl->loop >= LOOP_UNSET_SIZE_CLASS && - bg->size_class == BTRFS_BG_SZ_NONE) - return true; - return ffe_ctl->size_class == bg->size_class; -} - static int prepare_allocation_clustered(struct btrfs_fs_info *fs_info, struct find_free_extent_ctl *ffe_ctl, struct btrfs_space_info *space_info,
From: David Sterba dsterba@suse.com
[ Upstream commit ca283ea9920ac20ae23ed398b693db3121045019 ]
Continue adding const to parameters. This is for clarity and minor addition to safety. There are some minor effects, in the assembly code and .ko measured on release config.
Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/btrfs/backref.c | 6 +++--- fs/btrfs/block-group.c | 34 +++++++++++++++++----------------- fs/btrfs/block-group.h | 11 +++++------ fs/btrfs/block-rsv.c | 2 +- fs/btrfs/block-rsv.h | 2 +- fs/btrfs/ctree.c | 14 +++++++------- fs/btrfs/ctree.h | 6 +++--- fs/btrfs/discard.c | 4 ++-- fs/btrfs/file-item.c | 4 ++-- fs/btrfs/file-item.h | 2 +- fs/btrfs/inode-item.c | 10 +++++----- fs/btrfs/inode-item.h | 4 ++-- fs/btrfs/space-info.c | 17 ++++++++--------- fs/btrfs/space-info.h | 6 +++--- fs/btrfs/tree-mod-log.c | 14 +++++++------- fs/btrfs/tree-mod-log.h | 6 +++--- fs/btrfs/zoned.c | 2 +- fs/btrfs/zoned.h | 4 ++-- include/trace/events/btrfs.h | 6 +++--- 19 files changed, 76 insertions(+), 78 deletions(-)
diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c index a2ba1c7fc16a..10f803d0534e 100644 --- a/fs/btrfs/backref.c +++ b/fs/btrfs/backref.c @@ -222,8 +222,8 @@ static void free_pref(struct prelim_ref *ref) * A -1 return indicates ref1 is a 'lower' block than ref2, while 1 * indicates a 'higher' block. */ -static int prelim_ref_compare(struct prelim_ref *ref1, - struct prelim_ref *ref2) +static int prelim_ref_compare(const struct prelim_ref *ref1, + const struct prelim_ref *ref2) { if (ref1->level < ref2->level) return -1; @@ -254,7 +254,7 @@ static int prelim_ref_compare(struct prelim_ref *ref1, }
static void update_share_count(struct share_check *sc, int oldcount, - int newcount, struct prelim_ref *newref) + int newcount, const struct prelim_ref *newref) { if ((!sc) || (oldcount == 0 && newcount < 1)) return; diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c index 226e6434a58a..6a905f9505de 100644 --- a/fs/btrfs/block-group.c +++ b/fs/btrfs/block-group.c @@ -23,7 +23,7 @@ #include "extent-tree.h"
#ifdef CONFIG_BTRFS_DEBUG -int btrfs_should_fragment_free_space(struct btrfs_block_group *block_group) +int btrfs_should_fragment_free_space(const struct btrfs_block_group *block_group) { struct btrfs_fs_info *fs_info = block_group->fs_info;
@@ -40,9 +40,9 @@ int btrfs_should_fragment_free_space(struct btrfs_block_group *block_group) * * Should be called with balance_lock held */ -static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags) +static u64 get_restripe_target(const struct btrfs_fs_info *fs_info, u64 flags) { - struct btrfs_balance_control *bctl = fs_info->balance_ctl; + const struct btrfs_balance_control *bctl = fs_info->balance_ctl; u64 target = 0;
if (!bctl) @@ -1418,9 +1418,9 @@ static int inc_block_group_ro(struct btrfs_block_group *cache, int force) }
static bool clean_pinned_extents(struct btrfs_trans_handle *trans, - struct btrfs_block_group *bg) + const struct btrfs_block_group *bg) { - struct btrfs_fs_info *fs_info = bg->fs_info; + struct btrfs_fs_info *fs_info = trans->fs_info; struct btrfs_transaction *prev_trans = NULL; const u64 start = bg->start; const u64 end = start + bg->length - 1; @@ -1752,14 +1752,14 @@ static int reclaim_bgs_cmp(void *unused, const struct list_head *a, return bg1->used > bg2->used; }
-static inline bool btrfs_should_reclaim(struct btrfs_fs_info *fs_info) +static inline bool btrfs_should_reclaim(const struct btrfs_fs_info *fs_info) { if (btrfs_is_zoned(fs_info)) return btrfs_zoned_should_reclaim(fs_info); return true; }
-static bool should_reclaim_block_group(struct btrfs_block_group *bg, u64 bytes_freed) +static bool should_reclaim_block_group(const struct btrfs_block_group *bg, u64 bytes_freed) { const struct btrfs_space_info *space_info = bg->space_info; const int reclaim_thresh = READ_ONCE(space_info->bg_reclaim_threshold); @@ -1991,8 +1991,8 @@ void btrfs_mark_bg_to_reclaim(struct btrfs_block_group *bg) spin_unlock(&fs_info->unused_bgs_lock); }
-static int read_bg_from_eb(struct btrfs_fs_info *fs_info, struct btrfs_key *key, - struct btrfs_path *path) +static int read_bg_from_eb(struct btrfs_fs_info *fs_info, const struct btrfs_key *key, + const struct btrfs_path *path) { struct extent_map_tree *em_tree; struct extent_map *em; @@ -2044,7 +2044,7 @@ static int read_bg_from_eb(struct btrfs_fs_info *fs_info, struct btrfs_key *key,
static int find_first_block_group(struct btrfs_fs_info *fs_info, struct btrfs_path *path, - struct btrfs_key *key) + const struct btrfs_key *key) { struct btrfs_root *root = btrfs_block_group_root(fs_info); int ret; @@ -2636,8 +2636,8 @@ static int insert_block_group_item(struct btrfs_trans_handle *trans, }
static int insert_dev_extent(struct btrfs_trans_handle *trans, - struct btrfs_device *device, u64 chunk_offset, - u64 start, u64 num_bytes) + const struct btrfs_device *device, u64 chunk_offset, + u64 start, u64 num_bytes) { struct btrfs_fs_info *fs_info = device->fs_info; struct btrfs_root *root = fs_info->dev_root; @@ -2787,7 +2787,7 @@ void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans) * For extent tree v2 we use the block_group_item->chunk_offset to point at our * global root id. For v1 it's always set to BTRFS_FIRST_CHUNK_TREE_OBJECTID. */ -static u64 calculate_global_root_id(struct btrfs_fs_info *fs_info, u64 offset) +static u64 calculate_global_root_id(const struct btrfs_fs_info *fs_info, u64 offset) { u64 div = SZ_1G; u64 index; @@ -3823,8 +3823,8 @@ static void force_metadata_allocation(struct btrfs_fs_info *info) } }
-static int should_alloc_chunk(struct btrfs_fs_info *fs_info, - struct btrfs_space_info *sinfo, int force) +static int should_alloc_chunk(const struct btrfs_fs_info *fs_info, + const struct btrfs_space_info *sinfo, int force) { u64 bytes_used = btrfs_space_info_used(sinfo, false); u64 thresh; @@ -4199,7 +4199,7 @@ int btrfs_chunk_alloc(struct btrfs_trans_handle *trans, u64 flags, return ret; }
-static u64 get_profile_num_devs(struct btrfs_fs_info *fs_info, u64 type) +static u64 get_profile_num_devs(const struct btrfs_fs_info *fs_info, u64 type) { u64 num_dev;
@@ -4606,7 +4606,7 @@ int btrfs_use_block_group_size_class(struct btrfs_block_group *bg, return 0; }
-bool btrfs_block_group_should_use_size_class(struct btrfs_block_group *bg) +bool btrfs_block_group_should_use_size_class(const struct btrfs_block_group *bg) { if (btrfs_is_zoned(bg->fs_info)) return false; diff --git a/fs/btrfs/block-group.h b/fs/btrfs/block-group.h index 089979981e4a..a8a6a21e393d 100644 --- a/fs/btrfs/block-group.h +++ b/fs/btrfs/block-group.h @@ -250,7 +250,7 @@ struct btrfs_block_group { enum btrfs_block_group_size_class size_class; };
-static inline u64 btrfs_block_group_end(struct btrfs_block_group *block_group) +static inline u64 btrfs_block_group_end(const struct btrfs_block_group *block_group) { return (block_group->start + block_group->length); } @@ -262,8 +262,7 @@ static inline bool btrfs_is_block_group_used(const struct btrfs_block_group *bg) return (bg->used > 0 || bg->reserved > 0 || bg->pinned > 0); }
-static inline bool btrfs_is_block_group_data_only( - struct btrfs_block_group *block_group) +static inline bool btrfs_is_block_group_data_only(const struct btrfs_block_group *block_group) { /* * In mixed mode the fragmentation is expected to be high, lowering the @@ -274,7 +273,7 @@ static inline bool btrfs_is_block_group_data_only( }
#ifdef CONFIG_BTRFS_DEBUG -int btrfs_should_fragment_free_space(struct btrfs_block_group *block_group); +int btrfs_should_fragment_free_space(const struct btrfs_block_group *block_group); #endif
struct btrfs_block_group *btrfs_lookup_first_block_group( @@ -355,7 +354,7 @@ static inline u64 btrfs_system_alloc_profile(struct btrfs_fs_info *fs_info) return btrfs_get_alloc_profile(fs_info, BTRFS_BLOCK_GROUP_SYSTEM); }
-static inline int btrfs_block_group_done(struct btrfs_block_group *cache) +static inline int btrfs_block_group_done(const struct btrfs_block_group *cache) { smp_mb(); return cache->cached == BTRFS_CACHE_FINISHED || @@ -372,6 +371,6 @@ enum btrfs_block_group_size_class btrfs_calc_block_group_size_class(u64 size); int btrfs_use_block_group_size_class(struct btrfs_block_group *bg, enum btrfs_block_group_size_class size_class, bool force_wrong_size_class); -bool btrfs_block_group_should_use_size_class(struct btrfs_block_group *bg); +bool btrfs_block_group_should_use_size_class(const struct btrfs_block_group *bg);
#endif /* BTRFS_BLOCK_GROUP_H */ diff --git a/fs/btrfs/block-rsv.c b/fs/btrfs/block-rsv.c index db8da4e7b228..97084ea3af0c 100644 --- a/fs/btrfs/block-rsv.c +++ b/fs/btrfs/block-rsv.c @@ -547,7 +547,7 @@ struct btrfs_block_rsv *btrfs_use_block_rsv(struct btrfs_trans_handle *trans, return ERR_PTR(ret); }
-int btrfs_check_trunc_cache_free_space(struct btrfs_fs_info *fs_info, +int btrfs_check_trunc_cache_free_space(const struct btrfs_fs_info *fs_info, struct btrfs_block_rsv *rsv) { u64 needed_bytes; diff --git a/fs/btrfs/block-rsv.h b/fs/btrfs/block-rsv.h index 43a9a6b5a79f..3c9a15f59731 100644 --- a/fs/btrfs/block-rsv.h +++ b/fs/btrfs/block-rsv.h @@ -82,7 +82,7 @@ void btrfs_release_global_block_rsv(struct btrfs_fs_info *fs_info); struct btrfs_block_rsv *btrfs_use_block_rsv(struct btrfs_trans_handle *trans, struct btrfs_root *root, u32 blocksize); -int btrfs_check_trunc_cache_free_space(struct btrfs_fs_info *fs_info, +int btrfs_check_trunc_cache_free_space(const struct btrfs_fs_info *fs_info, struct btrfs_block_rsv *rsv); static inline void btrfs_unuse_block_rsv(struct btrfs_fs_info *fs_info, struct btrfs_block_rsv *block_rsv, diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index 4b21ca49b666..da49ccb991da 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -2712,7 +2712,7 @@ int btrfs_get_next_valid_item(struct btrfs_root *root, struct btrfs_key *key, * */ static void fixup_low_keys(struct btrfs_trans_handle *trans, - struct btrfs_path *path, + const struct btrfs_path *path, struct btrfs_disk_key *key, int level) { int i; @@ -2742,7 +2742,7 @@ static void fixup_low_keys(struct btrfs_trans_handle *trans, * that the new key won't break the order */ void btrfs_set_item_key_safe(struct btrfs_trans_handle *trans, - struct btrfs_path *path, + const struct btrfs_path *path, const struct btrfs_key *new_key) { struct btrfs_fs_info *fs_info = trans->fs_info; @@ -2808,8 +2808,8 @@ void btrfs_set_item_key_safe(struct btrfs_trans_handle *trans, * is correct, we only need to bother the last key of @left and the first * key of @right. */ -static bool check_sibling_keys(struct extent_buffer *left, - struct extent_buffer *right) +static bool check_sibling_keys(const struct extent_buffer *left, + const struct extent_buffer *right) { struct btrfs_key left_last; struct btrfs_key right_first; @@ -3077,7 +3077,7 @@ static noinline int insert_new_root(struct btrfs_trans_handle *trans, * blocknr is the block the key points to. */ static int insert_ptr(struct btrfs_trans_handle *trans, - struct btrfs_path *path, + const struct btrfs_path *path, struct btrfs_disk_key *key, u64 bytenr, int slot, int level) { @@ -4168,7 +4168,7 @@ int btrfs_split_item(struct btrfs_trans_handle *trans, * the front. */ void btrfs_truncate_item(struct btrfs_trans_handle *trans, - struct btrfs_path *path, u32 new_size, int from_end) + const struct btrfs_path *path, u32 new_size, int from_end) { int slot; struct extent_buffer *leaf; @@ -4260,7 +4260,7 @@ void btrfs_truncate_item(struct btrfs_trans_handle *trans, * make the item pointed to by the path bigger, data_size is the added size. */ void btrfs_extend_item(struct btrfs_trans_handle *trans, - struct btrfs_path *path, u32 data_size) + const struct btrfs_path *path, u32 data_size) { int slot; struct extent_buffer *leaf; diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 7df3ed2945b0..834af67fac23 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -521,7 +521,7 @@ int btrfs_previous_item(struct btrfs_root *root, int btrfs_previous_extent_item(struct btrfs_root *root, struct btrfs_path *path, u64 min_objectid); void btrfs_set_item_key_safe(struct btrfs_trans_handle *trans, - struct btrfs_path *path, + const struct btrfs_path *path, const struct btrfs_key *new_key); struct extent_buffer *btrfs_root_node(struct btrfs_root *root); int btrfs_find_next_key(struct btrfs_root *root, struct btrfs_path *path, @@ -555,9 +555,9 @@ int btrfs_block_can_be_shared(struct btrfs_trans_handle *trans, int btrfs_del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, int level, int slot); void btrfs_extend_item(struct btrfs_trans_handle *trans, - struct btrfs_path *path, u32 data_size); + const struct btrfs_path *path, u32 data_size); void btrfs_truncate_item(struct btrfs_trans_handle *trans, - struct btrfs_path *path, u32 new_size, int from_end); + const struct btrfs_path *path, u32 new_size, int from_end); int btrfs_split_item(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, diff --git a/fs/btrfs/discard.c b/fs/btrfs/discard.c index 3981c941f5b5..d6eef4bd9e9d 100644 --- a/fs/btrfs/discard.c +++ b/fs/btrfs/discard.c @@ -68,7 +68,7 @@ static int discard_minlen[BTRFS_NR_DISCARD_LISTS] = { };
static struct list_head *get_discard_list(struct btrfs_discard_ctl *discard_ctl, - struct btrfs_block_group *block_group) + const struct btrfs_block_group *block_group) { return &discard_ctl->discard_list[block_group->discard_index]; } @@ -80,7 +80,7 @@ static struct list_head *get_discard_list(struct btrfs_discard_ctl *discard_ctl, * * Check if the file system is writeable and BTRFS_FS_DISCARD_RUNNING is set. */ -static bool btrfs_run_discard_work(struct btrfs_discard_ctl *discard_ctl) +static bool btrfs_run_discard_work(const struct btrfs_discard_ctl *discard_ctl) { struct btrfs_fs_info *fs_info = container_of(discard_ctl, struct btrfs_fs_info, diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c index 45cae356e89b..ea5759a689b9 100644 --- a/fs/btrfs/file-item.c +++ b/fs/btrfs/file-item.c @@ -153,7 +153,7 @@ static inline u32 max_ordered_sum_bytes(const struct btrfs_fs_info *fs_info) * Calculate the total size needed to allocate for an ordered sum structure * spanning @bytes in the file. */ -static int btrfs_ordered_sum_size(struct btrfs_fs_info *fs_info, unsigned long bytes) +static int btrfs_ordered_sum_size(const struct btrfs_fs_info *fs_info, unsigned long bytes) { return sizeof(struct btrfs_ordered_sum) + bytes_to_csum_size(fs_info, bytes); } @@ -1263,7 +1263,7 @@ int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
void btrfs_extent_item_to_extent_map(struct btrfs_inode *inode, const struct btrfs_path *path, - struct btrfs_file_extent_item *fi, + const struct btrfs_file_extent_item *fi, struct extent_map *em) { struct btrfs_fs_info *fs_info = inode->root->fs_info; diff --git a/fs/btrfs/file-item.h b/fs/btrfs/file-item.h index 04bd2d34efb1..2b1d08b88b61 100644 --- a/fs/btrfs/file-item.h +++ b/fs/btrfs/file-item.h @@ -62,7 +62,7 @@ int btrfs_lookup_csums_bitmap(struct btrfs_root *root, struct btrfs_path *path, unsigned long *csum_bitmap); void btrfs_extent_item_to_extent_map(struct btrfs_inode *inode, const struct btrfs_path *path, - struct btrfs_file_extent_item *fi, + const struct btrfs_file_extent_item *fi, struct extent_map *em); int btrfs_inode_clear_file_extent_range(struct btrfs_inode *inode, u64 start, u64 len); diff --git a/fs/btrfs/inode-item.c b/fs/btrfs/inode-item.c index d3ff97374d48..ab741a578424 100644 --- a/fs/btrfs/inode-item.c +++ b/fs/btrfs/inode-item.c @@ -15,7 +15,7 @@ #include "extent-tree.h" #include "file-item.h"
-struct btrfs_inode_ref *btrfs_find_name_in_backref(struct extent_buffer *leaf, +struct btrfs_inode_ref *btrfs_find_name_in_backref(const struct extent_buffer *leaf, int slot, const struct fscrypt_str *name) { @@ -43,7 +43,7 @@ struct btrfs_inode_ref *btrfs_find_name_in_backref(struct extent_buffer *leaf, }
struct btrfs_inode_extref *btrfs_find_name_in_ext_backref( - struct extent_buffer *leaf, int slot, u64 ref_objectid, + const struct extent_buffer *leaf, int slot, u64 ref_objectid, const struct fscrypt_str *name) { struct btrfs_inode_extref *extref; @@ -424,9 +424,9 @@ int btrfs_lookup_inode(struct btrfs_trans_handle *trans, struct btrfs_root return ret; }
-static inline void btrfs_trace_truncate(struct btrfs_inode *inode, - struct extent_buffer *leaf, - struct btrfs_file_extent_item *fi, +static inline void btrfs_trace_truncate(const struct btrfs_inode *inode, + const struct extent_buffer *leaf, + const struct btrfs_file_extent_item *fi, u64 offset, int extent_type, int slot) { if (!inode) diff --git a/fs/btrfs/inode-item.h b/fs/btrfs/inode-item.h index ede43b6c6559..d43633d5620f 100644 --- a/fs/btrfs/inode-item.h +++ b/fs/btrfs/inode-item.h @@ -100,11 +100,11 @@ struct btrfs_inode_extref *btrfs_lookup_inode_extref( u64 inode_objectid, u64 ref_objectid, int ins_len, int cow);
-struct btrfs_inode_ref *btrfs_find_name_in_backref(struct extent_buffer *leaf, +struct btrfs_inode_ref *btrfs_find_name_in_backref(const struct extent_buffer *leaf, int slot, const struct fscrypt_str *name); struct btrfs_inode_extref *btrfs_find_name_in_ext_backref( - struct extent_buffer *leaf, int slot, u64 ref_objectid, + const struct extent_buffer *leaf, int slot, u64 ref_objectid, const struct fscrypt_str *name);
#endif diff --git a/fs/btrfs/space-info.c b/fs/btrfs/space-info.c index 581bdd709ee0..27690c518f6d 100644 --- a/fs/btrfs/space-info.c +++ b/fs/btrfs/space-info.c @@ -162,7 +162,7 @@ * thing with or without extra unallocated space. */
-u64 __pure btrfs_space_info_used(struct btrfs_space_info *s_info, +u64 __pure btrfs_space_info_used(const struct btrfs_space_info *s_info, bool may_use_included) { ASSERT(s_info); @@ -342,7 +342,7 @@ struct btrfs_space_info *btrfs_find_space_info(struct btrfs_fs_info *info, }
static u64 calc_available_free_space(struct btrfs_fs_info *fs_info, - struct btrfs_space_info *space_info, + const struct btrfs_space_info *space_info, enum btrfs_reserve_flush_enum flush) { u64 profile; @@ -378,7 +378,7 @@ static u64 calc_available_free_space(struct btrfs_fs_info *fs_info, }
int btrfs_can_overcommit(struct btrfs_fs_info *fs_info, - struct btrfs_space_info *space_info, u64 bytes, + const struct btrfs_space_info *space_info, u64 bytes, enum btrfs_reserve_flush_enum flush) { u64 avail; @@ -483,8 +483,8 @@ static void dump_global_block_rsv(struct btrfs_fs_info *fs_info) DUMP_BLOCK_RSV(fs_info, delayed_refs_rsv); }
-static void __btrfs_dump_space_info(struct btrfs_fs_info *fs_info, - struct btrfs_space_info *info) +static void __btrfs_dump_space_info(const struct btrfs_fs_info *fs_info, + const struct btrfs_space_info *info) { const char *flag_str = space_info_flag_to_str(info); lockdep_assert_held(&info->lock); @@ -807,9 +807,8 @@ static void flush_space(struct btrfs_fs_info *fs_info, return; }
-static inline u64 -btrfs_calc_reclaim_metadata_size(struct btrfs_fs_info *fs_info, - struct btrfs_space_info *space_info) +static u64 btrfs_calc_reclaim_metadata_size(struct btrfs_fs_info *fs_info, + const struct btrfs_space_info *space_info) { u64 used; u64 avail; @@ -834,7 +833,7 @@ btrfs_calc_reclaim_metadata_size(struct btrfs_fs_info *fs_info, }
static bool need_preemptive_reclaim(struct btrfs_fs_info *fs_info, - struct btrfs_space_info *space_info) + const struct btrfs_space_info *space_info) { const u64 global_rsv_size = btrfs_block_rsv_reserved(&fs_info->global_block_rsv); u64 ordered, delalloc; diff --git a/fs/btrfs/space-info.h b/fs/btrfs/space-info.h index 08a3bd10addc..b0187f25dbb5 100644 --- a/fs/btrfs/space-info.h +++ b/fs/btrfs/space-info.h @@ -165,7 +165,7 @@ struct reserve_ticket { wait_queue_head_t wait; };
-static inline bool btrfs_mixed_space_info(struct btrfs_space_info *space_info) +static inline bool btrfs_mixed_space_info(const struct btrfs_space_info *space_info) { return ((space_info->flags & BTRFS_BLOCK_GROUP_METADATA) && (space_info->flags & BTRFS_BLOCK_GROUP_DATA)); @@ -206,7 +206,7 @@ void btrfs_update_space_info_chunk_size(struct btrfs_space_info *space_info, u64 chunk_size); struct btrfs_space_info *btrfs_find_space_info(struct btrfs_fs_info *info, u64 flags); -u64 __pure btrfs_space_info_used(struct btrfs_space_info *s_info, +u64 __pure btrfs_space_info_used(const struct btrfs_space_info *s_info, bool may_use_included); void btrfs_clear_space_info_full(struct btrfs_fs_info *info); void btrfs_dump_space_info(struct btrfs_fs_info *fs_info, @@ -219,7 +219,7 @@ int btrfs_reserve_metadata_bytes(struct btrfs_fs_info *fs_info, void btrfs_try_granting_tickets(struct btrfs_fs_info *fs_info, struct btrfs_space_info *space_info); int btrfs_can_overcommit(struct btrfs_fs_info *fs_info, - struct btrfs_space_info *space_info, u64 bytes, + const struct btrfs_space_info *space_info, u64 bytes, enum btrfs_reserve_flush_enum flush);
static inline void btrfs_space_info_free_bytes_may_use( diff --git a/fs/btrfs/tree-mod-log.c b/fs/btrfs/tree-mod-log.c index 3df6153d5d5a..febc014a510d 100644 --- a/fs/btrfs/tree-mod-log.c +++ b/fs/btrfs/tree-mod-log.c @@ -171,7 +171,7 @@ static noinline int tree_mod_log_insert(struct btrfs_fs_info *fs_info, * write unlock fs_info::tree_mod_log_lock. */ static inline bool tree_mod_dont_log(struct btrfs_fs_info *fs_info, - struct extent_buffer *eb) + const struct extent_buffer *eb) { if (!test_bit(BTRFS_FS_TREE_MOD_LOG_USERS, &fs_info->flags)) return true; @@ -189,7 +189,7 @@ static inline bool tree_mod_dont_log(struct btrfs_fs_info *fs_info,
/* Similar to tree_mod_dont_log, but doesn't acquire any locks. */ static inline bool tree_mod_need_log(const struct btrfs_fs_info *fs_info, - struct extent_buffer *eb) + const struct extent_buffer *eb) { if (!test_bit(BTRFS_FS_TREE_MOD_LOG_USERS, &fs_info->flags)) return false; @@ -199,7 +199,7 @@ static inline bool tree_mod_need_log(const struct btrfs_fs_info *fs_info, return true; }
-static struct tree_mod_elem *alloc_tree_mod_elem(struct extent_buffer *eb, +static struct tree_mod_elem *alloc_tree_mod_elem(const struct extent_buffer *eb, int slot, enum btrfs_mod_log_op op) { @@ -222,7 +222,7 @@ static struct tree_mod_elem *alloc_tree_mod_elem(struct extent_buffer *eb, return tm; }
-int btrfs_tree_mod_log_insert_key(struct extent_buffer *eb, int slot, +int btrfs_tree_mod_log_insert_key(const struct extent_buffer *eb, int slot, enum btrfs_mod_log_op op) { struct tree_mod_elem *tm; @@ -259,7 +259,7 @@ int btrfs_tree_mod_log_insert_key(struct extent_buffer *eb, int slot, return ret; }
-static struct tree_mod_elem *tree_mod_log_alloc_move(struct extent_buffer *eb, +static struct tree_mod_elem *tree_mod_log_alloc_move(const struct extent_buffer *eb, int dst_slot, int src_slot, int nr_items) { @@ -279,7 +279,7 @@ static struct tree_mod_elem *tree_mod_log_alloc_move(struct extent_buffer *eb, return tm; }
-int btrfs_tree_mod_log_insert_move(struct extent_buffer *eb, +int btrfs_tree_mod_log_insert_move(const struct extent_buffer *eb, int dst_slot, int src_slot, int nr_items) { @@ -536,7 +536,7 @@ static struct tree_mod_elem *tree_mod_log_search(struct btrfs_fs_info *fs_info, }
int btrfs_tree_mod_log_eb_copy(struct extent_buffer *dst, - struct extent_buffer *src, + const struct extent_buffer *src, unsigned long dst_offset, unsigned long src_offset, int nr_items) diff --git a/fs/btrfs/tree-mod-log.h b/fs/btrfs/tree-mod-log.h index 94f10afeee97..5f94ab681fa4 100644 --- a/fs/btrfs/tree-mod-log.h +++ b/fs/btrfs/tree-mod-log.h @@ -31,7 +31,7 @@ void btrfs_put_tree_mod_seq(struct btrfs_fs_info *fs_info, int btrfs_tree_mod_log_insert_root(struct extent_buffer *old_root, struct extent_buffer *new_root, bool log_removal); -int btrfs_tree_mod_log_insert_key(struct extent_buffer *eb, int slot, +int btrfs_tree_mod_log_insert_key(const struct extent_buffer *eb, int slot, enum btrfs_mod_log_op op); int btrfs_tree_mod_log_free_eb(struct extent_buffer *eb); struct extent_buffer *btrfs_tree_mod_log_rewind(struct btrfs_fs_info *fs_info, @@ -41,11 +41,11 @@ struct extent_buffer *btrfs_tree_mod_log_rewind(struct btrfs_fs_info *fs_info, struct extent_buffer *btrfs_get_old_root(struct btrfs_root *root, u64 time_seq); int btrfs_old_root_level(struct btrfs_root *root, u64 time_seq); int btrfs_tree_mod_log_eb_copy(struct extent_buffer *dst, - struct extent_buffer *src, + const struct extent_buffer *src, unsigned long dst_offset, unsigned long src_offset, int nr_items); -int btrfs_tree_mod_log_insert_move(struct extent_buffer *eb, +int btrfs_tree_mod_log_insert_move(const struct extent_buffer *eb, int dst_slot, int src_slot, int nr_items); u64 btrfs_tree_mod_log_lowest_seq(struct btrfs_fs_info *fs_info); diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c index 197dfafbf401..0ec406cac748 100644 --- a/fs/btrfs/zoned.c +++ b/fs/btrfs/zoned.c @@ -2346,7 +2346,7 @@ void btrfs_free_zone_cache(struct btrfs_fs_info *fs_info) mutex_unlock(&fs_devices->device_list_mutex); }
-bool btrfs_zoned_should_reclaim(struct btrfs_fs_info *fs_info) +bool btrfs_zoned_should_reclaim(const struct btrfs_fs_info *fs_info) { struct btrfs_fs_devices *fs_devices = fs_info->fs_devices; struct btrfs_device *device; diff --git a/fs/btrfs/zoned.h b/fs/btrfs/zoned.h index b9cec523b778..448955641d11 100644 --- a/fs/btrfs/zoned.h +++ b/fs/btrfs/zoned.h @@ -77,7 +77,7 @@ void btrfs_schedule_zone_finish_bg(struct btrfs_block_group *bg, struct extent_buffer *eb); void btrfs_clear_data_reloc_bg(struct btrfs_block_group *bg); void btrfs_free_zone_cache(struct btrfs_fs_info *fs_info); -bool btrfs_zoned_should_reclaim(struct btrfs_fs_info *fs_info); +bool btrfs_zoned_should_reclaim(const struct btrfs_fs_info *fs_info); void btrfs_zoned_release_data_reloc_bg(struct btrfs_fs_info *fs_info, u64 logical, u64 length); int btrfs_zone_finish_one_bg(struct btrfs_fs_info *fs_info); @@ -237,7 +237,7 @@ static inline void btrfs_clear_data_reloc_bg(struct btrfs_block_group *bg) { }
static inline void btrfs_free_zone_cache(struct btrfs_fs_info *fs_info) { }
-static inline bool btrfs_zoned_should_reclaim(struct btrfs_fs_info *fs_info) +static inline bool btrfs_zoned_should_reclaim(const struct btrfs_fs_info *fs_info) { return false; } diff --git a/include/trace/events/btrfs.h b/include/trace/events/btrfs.h index 8ea1674069fe..f759109caeea 100644 --- a/include/trace/events/btrfs.h +++ b/include/trace/events/btrfs.h @@ -1857,7 +1857,7 @@ TRACE_EVENT(qgroup_update_counters,
TRACE_EVENT(qgroup_update_reserve,
- TP_PROTO(struct btrfs_fs_info *fs_info, struct btrfs_qgroup *qgroup, + TP_PROTO(const struct btrfs_fs_info *fs_info, const struct btrfs_qgroup *qgroup, s64 diff, int type),
TP_ARGS(fs_info, qgroup, diff, type), @@ -1883,7 +1883,7 @@ TRACE_EVENT(qgroup_update_reserve,
TRACE_EVENT(qgroup_meta_reserve,
- TP_PROTO(struct btrfs_root *root, s64 diff, int type), + TP_PROTO(const struct btrfs_root *root, s64 diff, int type),
TP_ARGS(root, diff, type),
@@ -1906,7 +1906,7 @@ TRACE_EVENT(qgroup_meta_reserve,
TRACE_EVENT(qgroup_meta_convert,
- TP_PROTO(struct btrfs_root *root, s64 diff), + TP_PROTO(const struct btrfs_root *root, s64 diff),
TP_ARGS(root, diff),
On Mon, Aug 18, 2025 at 10:27:53PM -0400, Sasha Levin wrote:
From: David Sterba dsterba@suse.com
[ Upstream commit ca283ea9920ac20ae23ed398b693db3121045019 ]
Continue adding const to parameters. This is for clarity and minor addition to safety. There are some minor effects, in the assembly code and .ko measured on release config.
Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Sasha Levin sashal@kernel.org
What's the rationale for adding this to stable? Parameter constification is for programmers and to have cleaner interfaces but there's hardly any stability improvement.
On Tue, Aug 19, 2025 at 02:18:37PM +0200, David Sterba wrote:
On Mon, Aug 18, 2025 at 10:27:53PM -0400, Sasha Levin wrote:
From: David Sterba dsterba@suse.com
[ Upstream commit ca283ea9920ac20ae23ed398b693db3121045019 ]
Continue adding const to parameters. This is for clarity and minor addition to safety. There are some minor effects, in the assembly code and .ko measured on release config.
Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Sasha Levin sashal@kernel.org
What's the rationale for adding this to stable? Parameter constification is for programmers and to have cleaner interfaces but there's hardly any stability improvement.
When patches that assume that params are consts get backported, they tend to break the build on older trees that don't have these "constification" changes.
In this case, without this patch, backporting 807d9023e75f ("btrfs: fix ssd_spread overallocation") will cause the build error below, which is what made Greg generate this FAILED email:
fs/btrfs/extent-tree.c: In function ‘find_free_extent_check_size_class’: fs/btrfs/extent-tree.c:3538:54: error: passing argument 1 of ‘btrfs_block_group_should_use_size_class’ discards ‘const’ qualifier from pointer target type [-Werror=discarded-qualifiers] 3538 | if (!btrfs_block_group_should_use_size_class(bg)) | ^~ In file included from fs/btrfs/extent-tree.h:7, from fs/btrfs/extent-tree.c:20: fs/btrfs/block-group.h:375:72: note: expected ‘struct btrfs_block_group *’ but argument is of type ‘const struct btrfs_block_group *’ 375 | bool btrfs_block_group_should_use_size_class(struct btrfs_block_group *bg); | ~~~~~~~~~~~~~~~~~~~~~~~~~~^~
So we take the constification patch to fix the issue.
linux-stable-mirror@lists.linaro.org
-
David Sterba -
gregkh＠linuxfoundation.org -
Sasha Levin