From 2ffd2a6ad1d3a8213bb5805f45f49098fe615db1 Mon Sep 17 00:00:00 2001 From: Kemeng Shi Date: Fri, 5 Jan 2024 17:21:01 +0800 Subject: ext4: remove unnecessary parameter "needed" in ext4_discard_preallocations The "needed" controls the number of ext4_prealloc_space to discard in ext4_discard_preallocations. Function ext4_discard_preallocations is supposed to discard all non-used preallocated blocks when "needed" is 0 and now ext4_discard_preallocations is always called with "needed" = 0. Remove unnecessary parameter "needed" and remove all non-used preallocated spaces in ext4_discard_preallocations to simplify the code. Note: If count of non-used preallocated spaces could be more than UINT_MAX, there was a memory leak as some non-used preallocated spaces are left ununsed and this commit will fix it. Otherwise, there is no behavior change. Signed-off-by: Kemeng Shi Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20240105092102.496631-9-shikemeng@huaweicloud.com Signed-off-by: Theodore Ts'o --- fs/ext4/inode.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'fs/ext4/inode.c') diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 5af1b0b8680e..4cae8698f70c 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -371,7 +371,7 @@ void ext4_da_update_reserve_space(struct inode *inode, */ if ((ei->i_reserved_data_blocks == 0) && !inode_is_open_for_write(inode)) - ext4_discard_preallocations(inode, 0); + ext4_discard_preallocations(inode); } static int __check_block_validity(struct inode *inode, const char *func, @@ -4017,7 +4017,7 @@ int ext4_punch_hole(struct file *file, loff_t offset, loff_t length) if (stop_block > first_block) { down_write(&EXT4_I(inode)->i_data_sem); - ext4_discard_preallocations(inode, 0); + ext4_discard_preallocations(inode); ext4_es_remove_extent(inode, first_block, stop_block - first_block); @@ -4170,7 +4170,7 @@ int ext4_truncate(struct inode *inode) down_write(&EXT4_I(inode)->i_data_sem); - ext4_discard_preallocations(inode, 0); + ext4_discard_preallocations(inode); if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) err = ext4_ext_truncate(handle, inode); -- cgit v1.2.3 From 3fcc2b887a1ba4c1f45319cd8c54daa263ecbc36 Mon Sep 17 00:00:00 2001 From: Zhang Yi Date: Sat, 27 Jan 2024 09:58:00 +0800 Subject: ext4: refactor ext4_da_map_blocks() Refactor and cleanup ext4_da_map_blocks(), reduce some unnecessary parameters and branches, no logic changes. Signed-off-by: Zhang Yi Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20240127015825.1608160-2-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o --- fs/ext4/inode.c | 39 +++++++++++++++++---------------------- 1 file changed, 17 insertions(+), 22 deletions(-) (limited to 'fs/ext4/inode.c') diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 4cae8698f70c..bbd5ee6dd3f3 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -1704,7 +1704,6 @@ static int ext4_da_map_blocks(struct inode *inode, sector_t iblock, /* Lookup extent status tree firstly */ if (ext4_es_lookup_extent(inode, iblock, NULL, &es)) { if (ext4_es_is_hole(&es)) { - retval = 0; down_read(&EXT4_I(inode)->i_data_sem); goto add_delayed; } @@ -1749,26 +1748,9 @@ static int ext4_da_map_blocks(struct inode *inode, sector_t iblock, retval = ext4_ext_map_blocks(NULL, inode, map, 0); else retval = ext4_ind_map_blocks(NULL, inode, map, 0); - -add_delayed: - if (retval == 0) { - int ret; - - /* - * XXX: __block_prepare_write() unmaps passed block, - * is it OK? - */ - - ret = ext4_insert_delayed_block(inode, map->m_lblk); - if (ret != 0) { - retval = ret; - goto out_unlock; - } - - map_bh(bh, inode->i_sb, invalid_block); - set_buffer_new(bh); - set_buffer_delay(bh); - } else if (retval > 0) { + if (retval < 0) + goto out_unlock; + if (retval > 0) { unsigned int status; if (unlikely(retval != map->m_len)) { @@ -1783,11 +1765,24 @@ add_delayed: EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN; ext4_es_insert_extent(inode, map->m_lblk, map->m_len, map->m_pblk, status); + goto out_unlock; } +add_delayed: + /* + * XXX: __block_prepare_write() unmaps passed block, + * is it OK? + */ + retval = ext4_insert_delayed_block(inode, map->m_lblk); + if (retval) + goto out_unlock; + + map_bh(bh, inode->i_sb, invalid_block); + set_buffer_new(bh); + set_buffer_delay(bh); + out_unlock: up_read((&EXT4_I(inode)->i_data_sem)); - return retval; } -- cgit v1.2.3 From acf795dc161f3cf481db20f05db4250714e375e5 Mon Sep 17 00:00:00 2001 From: Zhang Yi Date: Sat, 27 Jan 2024 09:58:01 +0800 Subject: ext4: convert to exclusive lock while inserting delalloc extents ext4_da_map_blocks() only hold i_data_sem in shared mode and i_rwsem when inserting delalloc extents, it could be raced by another querying path of ext4_map_blocks() without i_rwsem, .e.g buffered read path. Suppose we buffered read a file containing just a hole, and without any cached extents tree, then it is raced by another delayed buffered write to the same area or the near area belongs to the same hole, and the new delalloc extent could be overwritten to a hole extent. pread() pwrite() filemap_read_folio() ext4_mpage_readpages() ext4_map_blocks() down_read(i_data_sem) ext4_ext_determine_hole() //find hole ext4_ext_put_gap_in_cache() ext4_es_find_extent_range() //no delalloc extent ext4_da_map_blocks() down_read(i_data_sem) ext4_insert_delayed_block() //insert delalloc extent ext4_es_insert_extent() //overwrite delalloc extent to hole This race could lead to inconsistent delalloc extents tree and incorrect reserved space counter. Fix this by converting to hold i_data_sem in exclusive mode when adding a new delalloc extent in ext4_da_map_blocks(). Cc: stable@vger.kernel.org Signed-off-by: Zhang Yi Suggested-by: Jan Kara Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20240127015825.1608160-3-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o --- fs/ext4/inode.c | 25 +++++++++++-------------- 1 file changed, 11 insertions(+), 14 deletions(-) (limited to 'fs/ext4/inode.c') diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index bbd5ee6dd3f3..b040337501e3 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -1703,10 +1703,8 @@ static int ext4_da_map_blocks(struct inode *inode, sector_t iblock, /* Lookup extent status tree firstly */ if (ext4_es_lookup_extent(inode, iblock, NULL, &es)) { - if (ext4_es_is_hole(&es)) { - down_read(&EXT4_I(inode)->i_data_sem); + if (ext4_es_is_hole(&es)) goto add_delayed; - } /* * Delayed extent could be allocated by fallocate. @@ -1748,8 +1746,10 @@ static int ext4_da_map_blocks(struct inode *inode, sector_t iblock, retval = ext4_ext_map_blocks(NULL, inode, map, 0); else retval = ext4_ind_map_blocks(NULL, inode, map, 0); - if (retval < 0) - goto out_unlock; + if (retval < 0) { + up_read(&EXT4_I(inode)->i_data_sem); + return retval; + } if (retval > 0) { unsigned int status; @@ -1765,24 +1765,21 @@ static int ext4_da_map_blocks(struct inode *inode, sector_t iblock, EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN; ext4_es_insert_extent(inode, map->m_lblk, map->m_len, map->m_pblk, status); - goto out_unlock; + up_read(&EXT4_I(inode)->i_data_sem); + return retval; } + up_read(&EXT4_I(inode)->i_data_sem); add_delayed: - /* - * XXX: __block_prepare_write() unmaps passed block, - * is it OK? - */ + down_write(&EXT4_I(inode)->i_data_sem); retval = ext4_insert_delayed_block(inode, map->m_lblk); + up_write(&EXT4_I(inode)->i_data_sem); if (retval) - goto out_unlock; + return retval; map_bh(bh, inode->i_sb, invalid_block); set_buffer_new(bh); set_buffer_delay(bh); - -out_unlock: - up_read((&EXT4_I(inode)->i_data_sem)); return retval; } -- cgit v1.2.3 From 9f1118223aa080021fe9751fa221590654d27669 Mon Sep 17 00:00:00 2001 From: Zhang Yi Date: Sat, 27 Jan 2024 09:58:03 +0800 Subject: ext4: add a hole extent entry in cache after punch In order to cache hole extents in the extent status tree and keep the hole length as long as possible, re-add a hole entry to the cache just after punching a hole. Signed-off-by: Zhang Yi Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20240127015825.1608160-5-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o --- fs/ext4/inode.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'fs/ext4/inode.c') diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index b040337501e3..af205b416794 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -4007,12 +4007,12 @@ int ext4_punch_hole(struct file *file, loff_t offset, loff_t length) /* If there are blocks to remove, do it */ if (stop_block > first_block) { + ext4_lblk_t hole_len = stop_block - first_block; down_write(&EXT4_I(inode)->i_data_sem); ext4_discard_preallocations(inode); - ext4_es_remove_extent(inode, first_block, - stop_block - first_block); + ext4_es_remove_extent(inode, first_block, hole_len); if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) ret = ext4_ext_remove_space(inode, first_block, @@ -4021,6 +4021,8 @@ int ext4_punch_hole(struct file *file, loff_t offset, loff_t length) ret = ext4_ind_remove_space(handle, inode, first_block, stop_block); + ext4_es_insert_extent(inode, first_block, hole_len, ~0, + EXTENT_STATUS_HOLE); up_write(&EXT4_I(inode)->i_data_sem); } ext4_fc_track_range(handle, inode, first_block, stop_block); -- cgit v1.2.3 From 874eaba96d39334fe9c729ff631e65523616d4d8 Mon Sep 17 00:00:00 2001 From: Zhang Yi Date: Sat, 27 Jan 2024 09:58:04 +0800 Subject: ext4: make ext4_map_blocks() distinguish delalloc only extent Add a new map flag EXT4_MAP_DELAYED to indicate the mapping range is a delayed allocated only (not unwritten) one, and making ext4_map_blocks() can distinguish it, no longer mixing it with holes. Signed-off-by: Zhang Yi Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20240127015825.1608160-6-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o --- fs/ext4/ext4.h | 4 +++- fs/ext4/extents.c | 7 +++++-- fs/ext4/inode.c | 2 ++ 3 files changed, 10 insertions(+), 3 deletions(-) (limited to 'fs/ext4/inode.c') diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 786b6857ab47..023571f8dd1b 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -252,8 +252,10 @@ struct ext4_allocation_request { #define EXT4_MAP_MAPPED BIT(BH_Mapped) #define EXT4_MAP_UNWRITTEN BIT(BH_Unwritten) #define EXT4_MAP_BOUNDARY BIT(BH_Boundary) +#define EXT4_MAP_DELAYED BIT(BH_Delay) #define EXT4_MAP_FLAGS (EXT4_MAP_NEW | EXT4_MAP_MAPPED |\ - EXT4_MAP_UNWRITTEN | EXT4_MAP_BOUNDARY) + EXT4_MAP_UNWRITTEN | EXT4_MAP_BOUNDARY |\ + EXT4_MAP_DELAYED) struct ext4_map_blocks { ext4_fsblk_t m_pblk; diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index c5b54fb9eb8b..7669d154c05e 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -4076,8 +4076,11 @@ again: /* * The delalloc extent containing lblk, it must have been * added after ext4_map_blocks() checked the extent status - * tree, adjust the length to the delalloc extent's after - * lblk. + * tree so we are not holding i_rwsem and delalloc info is + * only stabilized by i_data_sem we are going to release + * soon. Don't modify the extent status tree and report + * extent as a hole, just adjust the length to the delalloc + * extent's after lblk. */ len = es.es_lblk + es.es_len - lblk; return len; diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index af205b416794..60f0d2dc1c37 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -515,6 +515,8 @@ int ext4_map_blocks(handle_t *handle, struct inode *inode, map->m_len = retval; } else if (ext4_es_is_delayed(&es) || ext4_es_is_hole(&es)) { map->m_pblk = 0; + map->m_flags |= ext4_es_is_delayed(&es) ? + EXT4_MAP_DELAYED : 0; retval = es.es_len - (map->m_lblk - es.es_lblk); if (retval > map->m_len) retval = map->m_len; -- cgit v1.2.3 From ec9d669eba4c276d00af88951947fe0e82a6b84c Mon Sep 17 00:00:00 2001 From: Zhang Yi Date: Sat, 27 Jan 2024 09:58:05 +0800 Subject: ext4: make ext4_set_iomap() recognize IOMAP_DELALLOC map type Since ext4_map_blocks() can recognize a delayed allocated only extent, make ext4_set_iomap() can also recognize it, and remove the useless separate check in ext4_iomap_begin_report(). Signed-off-by: Zhang Yi Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20240127015825.1608160-7-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o --- fs/ext4/inode.c | 32 +++----------------------------- 1 file changed, 3 insertions(+), 29 deletions(-) (limited to 'fs/ext4/inode.c') diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 60f0d2dc1c37..2ccf3b5e3a7c 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -3262,6 +3262,9 @@ static void ext4_set_iomap(struct inode *inode, struct iomap *iomap, iomap->addr = (u64) map->m_pblk << blkbits; if (flags & IOMAP_DAX) iomap->addr += EXT4_SB(inode->i_sb)->s_dax_part_off; + } else if (map->m_flags & EXT4_MAP_DELAYED) { + iomap->type = IOMAP_DELALLOC; + iomap->addr = IOMAP_NULL_ADDR; } else { iomap->type = IOMAP_HOLE; iomap->addr = IOMAP_NULL_ADDR; @@ -3424,35 +3427,11 @@ const struct iomap_ops ext4_iomap_overwrite_ops = { .iomap_end = ext4_iomap_end, }; -static bool ext4_iomap_is_delalloc(struct inode *inode, - struct ext4_map_blocks *map) -{ - struct extent_status es; - ext4_lblk_t offset = 0, end = map->m_lblk + map->m_len - 1; - - ext4_es_find_extent_range(inode, &ext4_es_is_delayed, - map->m_lblk, end, &es); - - if (!es.es_len || es.es_lblk > end) - return false; - - if (es.es_lblk > map->m_lblk) { - map->m_len = es.es_lblk - map->m_lblk; - return false; - } - - offset = map->m_lblk - es.es_lblk; - map->m_len = es.es_len - offset; - - return true; -} - static int ext4_iomap_begin_report(struct inode *inode, loff_t offset, loff_t length, unsigned int flags, struct iomap *iomap, struct iomap *srcmap) { int ret; - bool delalloc = false; struct ext4_map_blocks map; u8 blkbits = inode->i_blkbits; @@ -3493,13 +3472,8 @@ static int ext4_iomap_begin_report(struct inode *inode, loff_t offset, ret = ext4_map_blocks(NULL, inode, &map, 0); if (ret < 0) return ret; - if (ret == 0) - delalloc = ext4_iomap_is_delalloc(inode, &map); - set_iomap: ext4_set_iomap(inode, iomap, &map, offset, length, flags); - if (delalloc && iomap->type == IOMAP_HOLE) - iomap->type = IOMAP_DELALLOC; return 0; } -- cgit v1.2.3