{"id":2226012,"url":"http://patchwork.ozlabs.org/api/1.2/patches/2226012/?format=json","web_url":"http://patchwork.ozlabs.org/project/linux-ext4/patch/20260422021042.4157510-6-yi.zhang@huaweicloud.com/","project":{"id":8,"url":"http://patchwork.ozlabs.org/api/1.2/projects/8/?format=json","name":"Linux ext4 filesystem development","link_name":"linux-ext4","list_id":"linux-ext4.vger.kernel.org","list_email":"linux-ext4@vger.kernel.org","web_url":null,"scm_url":null,"webscm_url":null,"list_archive_url":"","list_archive_url_format":"","commit_url_format":""},"msgid":"<20260422021042.4157510-6-yi.zhang@huaweicloud.com>","list_archive_url":null,"date":"2026-04-22T02:10:25","name":"[v3,05/22] ext4: implement buffered read path using iomap","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"5461a87e95437655f5451a08b0e12906ca9bcff0","submitter":{"id":85428,"url":"http://patchwork.ozlabs.org/api/1.2/people/85428/?format=json","name":"Zhang Yi","email":"yi.zhang@huaweicloud.com"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/linux-ext4/patch/20260422021042.4157510-6-yi.zhang@huaweicloud.com/mbox/","series":[{"id":500911,"url":"http://patchwork.ozlabs.org/api/1.2/series/500911/?format=json","web_url":"http://patchwork.ozlabs.org/project/linux-ext4/list/?series=500911","date":"2026-04-22T02:10:23","name":"ext4: use iomap for regular file's buffered I/O path","version":3,"mbox":"http://patchwork.ozlabs.org/series/500911/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2226012/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2226012/checks/","tags":{},"related":[],"headers":{"Return-Path":"\n ","X-Original-To":["incoming@patchwork.ozlabs.org","linux-ext4@vger.kernel.org"],"Delivered-To":["patchwork-incoming@legolas.ozlabs.org","patchwork-incoming@ozlabs.org"],"Authentication-Results":["legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=ozlabs.org\n (client-ip=2404:9400:2221:ea00::3; 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This provides the read_folio()\nand readahead() callbacks for ext4_iomap_aops. The implementation\nintroduces:\n\n - ext4_iomap_map_blocks(): Helper function to query extent mappings for\n a given read range using ext4_map_blocks() and convert the mapping\n information to iomap type\n - ext4_iomap_buffered_read_begin(): The iomap_begin callback that maps\n blocks, validates filesystem state, and populates the iomap. It\n returns -ERANGE for inline data which is not yet supported.\n\nSigned-off-by: Zhang Yi \n---\n fs/ext4/inode.c | 45 ++++++++++++++++++++++++++++++++++++++++++++-\n 1 file changed, 44 insertions(+), 1 deletion(-)","diff":"diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c\nindex 9e9f421888ed..df21f6870ec4 100644\n--- a/fs/ext4/inode.c\n+++ b/fs/ext4/inode.c\n@@ -3908,14 +3908,57 @@ const struct iomap_ops ext4_iomap_report_ops = {\n \t.iomap_begin = ext4_iomap_begin_report,\n };\n \n+static int ext4_iomap_map_blocks(struct inode *inode, loff_t offset,\n+\t\tloff_t length, struct ext4_map_blocks *map)\n+{\n+\tu8 blkbits = inode->i_blkbits;\n+\n+\tif ((offset >> blkbits) > EXT4_MAX_LOGICAL_BLOCK)\n+\t\treturn -EINVAL;\n+\n+\t/* Calculate the first and last logical blocks respectively. */\n+\tmap->m_lblk = offset >> blkbits;\n+\tmap->m_len = min_t(loff_t, (offset + length - 1) >> blkbits,\n+\t\t\t EXT4_MAX_LOGICAL_BLOCK) - map->m_lblk + 1;\n+\n+\treturn ext4_map_blocks(NULL, inode, map, 0);\n+}\n+\n+static int ext4_iomap_buffered_read_begin(struct inode *inode, loff_t offset,\n+\t\tloff_t length, unsigned int flags, struct iomap *iomap,\n+\t\tstruct iomap *srcmap)\n+{\n+\tstruct ext4_map_blocks map;\n+\tint ret;\n+\n+\tif (unlikely(ext4_forced_shutdown(inode->i_sb)))\n+\t\treturn -EIO;\n+\n+\t/* Inline data support is not yet available. */\n+\tif (WARN_ON_ONCE(ext4_has_inline_data(inode)))\n+\t\treturn -ERANGE;\n+\n+\tret = ext4_iomap_map_blocks(inode, offset, length, &map);\n+\tif (ret < 0)\n+\t\treturn ret;\n+\n+\text4_set_iomap(inode, iomap, &map, offset, length, flags);\n+\treturn 0;\n+}\n+\n+const struct iomap_ops ext4_iomap_buffered_read_ops = {\n+\t.iomap_begin = ext4_iomap_buffered_read_begin,\n+};\n+\n static int ext4_iomap_read_folio(struct file *file, struct folio *folio)\n {\n+\tiomap_bio_read_folio(folio, &ext4_iomap_buffered_read_ops);\n \treturn 0;\n }\n \n static void ext4_iomap_readahead(struct readahead_control *rac)\n {\n-\n+\tiomap_bio_readahead(rac, &ext4_iomap_buffered_read_ops);\n }\n \n static int ext4_iomap_writepages(struct address_space *mapping,\n","prefixes":["v3","05/22"]}