f2fs_read_data_large_folio() relies on f2fs_map_blocks() to decide whether a subpage should be zero-filled or queued to a read bio.
However, f2fs_map_blocks() can set F2FS_MAP_MAPPED for NULL_ADDR and NEW_ADDR in the non-DIO, no-create path. The large folio read code then treats such hole blocks as mapped blocks, and may account them in read_pages_pending and attempt to build bios for them, which can leave tasks stuck in readahead for heavily fragmented files. Add a helper, f2fs_block_needs_zeroing(), which detects NULL_ADDR and NEW_ADDR from struct f2fs_map_blocks. Use it to prioritize the zeroing path by checking f2fs_block_needs_zeroing() before (map.m_flags & F2FS_MAP_MAPPED) under got_it: label. Signed-off-by: Nanzhe Zhao <[email protected]> --- fs/f2fs/data.c | 21 +++++++++++++-------- 1 file changed, 13 insertions(+), 8 deletions(-) diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index 4bef04560924..66ab7a43a56f 100644 --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -2413,6 +2413,11 @@ static void ffs_detach_free(struct folio *folio) kmem_cache_free(ffs_entry_slab, ffs); } +static inline bool f2fs_block_needs_zeroing(const struct f2fs_map_blocks *map) +{ + return map->m_pblk == NULL_ADDR || map->m_pblk == NEW_ADDR; +} + static int f2fs_read_data_large_folio(struct inode *inode, struct readahead_control *rac, struct folio *folio) { @@ -2468,14 +2473,7 @@ static int f2fs_read_data_large_folio(struct inode *inode, if (ret) goto err_out; got_it: - if ((map.m_flags & F2FS_MAP_MAPPED)) { - block_nr = map.m_pblk + index - map.m_lblk; - if (!f2fs_is_valid_blkaddr(F2FS_I_SB(inode), block_nr, - DATA_GENERIC_ENHANCE_READ)) { - ret = -EFSCORRUPTED; - goto err_out; - } - } else { + if ((f2fs_block_needs_zeroing(&map))) { folio_zero_range(folio, offset << PAGE_SHIFT, PAGE_SIZE); if (f2fs_need_verity(inode, index) && !fsverity_verify_page(folio_file_page(folio, @@ -2484,6 +2482,13 @@ static int f2fs_read_data_large_folio(struct inode *inode, goto err_out; } continue; + } else if((map.m_flags & F2FS_MAP_MAPPED)) { + block_nr = map.m_pblk + index - map.m_lblk; + if (!f2fs_is_valid_blkaddr(F2FS_I_SB(inode), block_nr, + DATA_GENERIC_ENHANCE_READ)) { + ret = -EFSCORRUPTED; + goto err_out; + } } /* We must increment read_pages_pending before possible BIOs submitting -- 2.34.1 _______________________________________________ Linux-f2fs-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
