diff options
| author | Zhang Yi <yi.zhang@huawei.com> | 2025-07-07 22:08:14 +0800 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2025-07-14 23:48:15 -0400 |
| commit | b12f423d598fd874df9ecfb2436789d582fda8e6 (patch) | |
| tree | bec5abed31fbf42398700ecc878d2fafd6896e4d | |
| parent | 5137d6c8906b55b3c7b5d1aa5a549753ec8520f5 (diff) | |
ext4: limit the maximum folio order
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+hgNWZEa9cQLbahA1+xg@mail.gmail.com/
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>
| -rw-r--r-- | fs/ext4/ext4.h | 2 | ||||
| -rw-r--r-- | fs/ext4/ialloc.c | 3 | ||||
| -rw-r--r-- | 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 f705046ba6c6..9ac0a7d4fa0c 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 @@ got: } } - 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 4a0ba009c88e..8bdf2029ebc7 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -5179,7 +5179,7 @@ error: 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; @@ -5196,6 +5196,22 @@ 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) @@ -5513,8 +5529,8 @@ 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); /* |