6.16-stable review patch. If anyone has any objections, please let me know.
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From: Zhang Yi yi.zhang@huawei.com
[ Upstream commit b12f423d598fd874df9ecfb2436789d582fda8e6 ]
In environments with a page size of 64KB, the maximum size of a folio can reach up to 128MB. Consequently, during the write-back of folios, the 'rsv_blocks' will be overestimated to 1,577, which can make pressure on the journal space where the journal is small. This can easily exceed the limit of a single transaction. Besides, an excessively large folio is meaningless and will instead increase the overhead of traversing the bhs within the folio. Therefore, limit the maximum order of a folio to 2048 filesystem blocks.
Reported-by: Naresh Kamboju naresh.kamboju@linaro.org Reported-by: Joseph Qi jiangqi903@gmail.com Closes: https://lore.kernel.org/linux-ext4/CA+G9fYsyYQ3ZL4xaSg1-Tt5Evto7Zd+hgNWZEa9c... Signed-off-by: Zhang Yi yi.zhang@huawei.com Tested-by: Joseph Qi joseph.qi@linux.alibaba.com Reviewed-by: Jan Kara jack@suse.cz Link: https://patch.msgid.link/20250707140814.542883-12-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o tytso@mit.edu Signed-off-by: Sasha Levin sashal@kernel.org --- fs/ext4/ext4.h | 2 +- fs/ext4/ialloc.c | 3 +-- fs/ext4/inode.c | 22 +++++++++++++++++++--- 3 files changed, 21 insertions(+), 6 deletions(-)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 18373de980f2..fe3366e98493 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -3020,7 +3020,7 @@ int ext4_walk_page_buffers(handle_t *handle, struct buffer_head *bh)); int do_journal_get_write_access(handle_t *handle, struct inode *inode, struct buffer_head *bh); -bool ext4_should_enable_large_folio(struct inode *inode); +void ext4_set_inode_mapping_order(struct inode *inode); #define FALL_BACK_TO_NONDELALLOC 1 #define CONVERT_INLINE_DATA 2
diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c index 79aa3df8d019..df4051613b29 100644 --- a/fs/ext4/ialloc.c +++ b/fs/ext4/ialloc.c @@ -1335,8 +1335,7 @@ struct inode *__ext4_new_inode(struct mnt_idmap *idmap, } }
- if (ext4_should_enable_large_folio(inode)) - mapping_set_large_folios(inode->i_mapping); + ext4_set_inode_mapping_order(inode);
ext4_update_inode_fsync_trans(handle, inode, 1);
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index ee4129b5ecce..0f316632b8dd 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -5107,7 +5107,7 @@ static int check_igot_inode(struct inode *inode, ext4_iget_flags flags, return -EFSCORRUPTED; }
-bool ext4_should_enable_large_folio(struct inode *inode) +static bool ext4_should_enable_large_folio(struct inode *inode) { struct super_block *sb = inode->i_sb;
@@ -5124,6 +5124,22 @@ bool ext4_should_enable_large_folio(struct inode *inode) return true; }
+/* + * Limit the maximum folio order to 2048 blocks to prevent overestimation + * of reserve handle credits during the folio writeback in environments + * where the PAGE_SIZE exceeds 4KB. + */ +#define EXT4_MAX_PAGECACHE_ORDER(i) \ + umin(MAX_PAGECACHE_ORDER, (11 + (i)->i_blkbits - PAGE_SHIFT)) +void ext4_set_inode_mapping_order(struct inode *inode) +{ + if (!ext4_should_enable_large_folio(inode)) + return; + + mapping_set_folio_order_range(inode->i_mapping, 0, + EXT4_MAX_PAGECACHE_ORDER(inode)); +} + struct inode *__ext4_iget(struct super_block *sb, unsigned long ino, ext4_iget_flags flags, const char *function, unsigned int line) @@ -5441,8 +5457,8 @@ struct inode *__ext4_iget(struct super_block *sb, unsigned long ino, ret = -EFSCORRUPTED; goto bad_inode; } - if (ext4_should_enable_large_folio(inode)) - mapping_set_large_folios(inode->i_mapping); + + ext4_set_inode_mapping_order(inode);
ret = check_igot_inode(inode, flags, function, line); /*