5.4-stable review patch. If anyone has any objections, please let me know.
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From: Baokun Li libaokun1@huawei.com
[ Upstream commit 9649eb18c6288f514cacffdd699d5cd999c2f8f6 ]
In the extent status tree, we have extents which we can just drop without issues and extents we must not drop - this depends on the extent's status - currently ext4_es_is_delayed() extents must stay, others may be dropped.
A helper function is added to help determine if the current extent can be dropped, although only ext4_es_is_delayed() extents cannot be dropped currently.
Suggested-by: Jan Kara jack@suse.cz Signed-off-by: Baokun Li libaokun1@huawei.com Reviewed-by: Jan Kara jack@suse.cz Link: https://lore.kernel.org/r/20230424033846.4732-3-libaokun1@huawei.com Signed-off-by: Theodore Ts'o tytso@mit.edu Stable-dep-of: 8e387c89e96b ("ext4: make sure allocate pending entry not fail") Signed-off-by: Sasha Levin sashal@kernel.org --- fs/ext4/extents_status.c | 34 +++++++++++++++++++++------------- 1 file changed, 21 insertions(+), 13 deletions(-)
diff --git a/fs/ext4/extents_status.c b/fs/ext4/extents_status.c index cfd05e016f181..59812c5bbe1ba 100644 --- a/fs/ext4/extents_status.c +++ b/fs/ext4/extents_status.c @@ -439,6 +439,19 @@ static void ext4_es_list_del(struct inode *inode) spin_unlock(&sbi->s_es_lock); }
+/* + * Returns true if we cannot fail to allocate memory for this extent_status + * entry and cannot reclaim it until its status changes. + */ +static inline bool ext4_es_must_keep(struct extent_status *es) +{ + /* fiemap, bigalloc, and seek_data/hole need to use it. */ + if (ext4_es_is_delayed(es)) + return true; + + return false; +} + static struct extent_status * ext4_es_alloc_extent(struct inode *inode, ext4_lblk_t lblk, ext4_lblk_t len, ext4_fsblk_t pblk) @@ -451,10 +464,8 @@ ext4_es_alloc_extent(struct inode *inode, ext4_lblk_t lblk, ext4_lblk_t len, es->es_len = len; es->es_pblk = pblk;
- /* - * We don't count delayed extent because we never try to reclaim them - */ - if (!ext4_es_is_delayed(es)) { + /* We never try to reclaim a must kept extent, so we don't count it. */ + if (!ext4_es_must_keep(es)) { if (!EXT4_I(inode)->i_es_shk_nr++) ext4_es_list_add(inode); percpu_counter_inc(&EXT4_SB(inode->i_sb)-> @@ -472,8 +483,8 @@ static void ext4_es_free_extent(struct inode *inode, struct extent_status *es) EXT4_I(inode)->i_es_all_nr--; percpu_counter_dec(&EXT4_SB(inode->i_sb)->s_es_stats.es_stats_all_cnt);
- /* Decrease the shrink counter when this es is not delayed */ - if (!ext4_es_is_delayed(es)) { + /* Decrease the shrink counter when we can reclaim the extent. */ + if (!ext4_es_must_keep(es)) { BUG_ON(EXT4_I(inode)->i_es_shk_nr == 0); if (!--EXT4_I(inode)->i_es_shk_nr) ext4_es_list_del(inode); @@ -842,7 +853,7 @@ int ext4_es_insert_extent(struct inode *inode, ext4_lblk_t lblk, if (err == -ENOMEM && __es_shrink(EXT4_SB(inode->i_sb), 128, EXT4_I(inode))) goto retry; - if (err == -ENOMEM && !ext4_es_is_delayed(&newes)) + if (err == -ENOMEM && !ext4_es_must_keep(&newes)) err = 0;
if (sbi->s_cluster_ratio > 1 && test_opt(inode->i_sb, DELALLOC) && @@ -1683,11 +1694,8 @@ static int es_do_reclaim_extents(struct ext4_inode_info *ei, ext4_lblk_t end,
(*nr_to_scan)--; node = rb_next(&es->rb_node); - /* - * We can't reclaim delayed extent from status tree because - * fiemap, bigallic, and seek_data/hole need to use it. - */ - if (ext4_es_is_delayed(es)) + + if (ext4_es_must_keep(es)) goto next; if (ext4_es_is_referenced(es)) { ext4_es_clear_referenced(es); @@ -1751,7 +1759,7 @@ void ext4_clear_inode_es(struct inode *inode) while (node) { es = rb_entry(node, struct extent_status, rb_node); node = rb_next(node); - if (!ext4_es_is_delayed(es)) { + if (!ext4_es_must_keep(es)) { rb_erase(&es->rb_node, &tree->root); ext4_es_free_extent(inode, es); }