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Wong" , Carlos Maiolino , Alexander Viro , Jan Kara Cc: Christoph Hellwig , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, Tal Zussman X-Mailer: b4 0.14.3-dev-d7477 X-Developer-Signature: v=1; a=ed25519-sha256; t=1774464193; l=4833; i=tz2294@columbia.edu; s=20250528; h=from:subject:message-id; bh=vqYjVe4t0i/AiFArpSZ9mEXLlU4rnE2ZRBBMSnozEZ0=; b=gpmN0bZuDH/LOZGTVX2LWTAbwaNFAVtx+0hCaa/06cmF7hrJjYYHDM3SkZtVNTBPzJKHCu1Ro uxYVg0q9qKMB8UfKgMIhJOiUIQQkEPxysztQm+QmC6XaBib3Uj2eKTq X-Developer-Key: i=tz2294@columbia.edu; a=ed25519; pk=BIj5KdACscEOyAC0oIkeZqLB3L94fzBnDccEooxeM5Y= X-Proofpoint-GUID: 7sYZl1J7XwvtrMWTgtXWi1tK-NqqqOot X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwMzI1MDE0MiBTYWx0ZWRfX7QW5NSGluev7 mvHcLGtLOhudy+xtvzYJ+staI9BSoNrTep+fgReyDIc2rRLupb9TjEanTxBJVPlnIVf4vbVrQ0Z je1RMOYCKYhenRfyqdc/66cONm1jvswcDmuZq1Ng1WNQGxD2qnfwvpS3rJQtnULcNV0QOMFVv/W gxBx8MNrz1YFK8QC55btQuAjte8/iAdqokL67xEbslMl2TSruNlE9M8Xrjc7xv74C6ISlKiBJlE GFTkhJNFAVlspTaIOu8BlJzMIL+eHAbJ8l3Itmywi+qsqL2xD9x0IkPmSuCwQmd8VIvHMY/H+fp /W3Yu7ILlTLJBKiqtMA4wCVEIe94plmX51MCq3Pp4XVwSbvaESkUD++H5VsB98+QmaebHrcf1mR eg9QqLmZTM1zHYCetV+FhG2zrog4Jqui3OC70auaK/m5z6q4/gb4oszJPQlODF7wnsgAYAJuZpO kqm7/TLfcmz6Tr+tFWA== X-Authority-Analysis: v=2.4 cv=A/th/qWG c=1 sm=1 tr=0 ts=69c437e3 cx=c_pps a=JbAStetqSzwMeJznSMzCyw==:117 a=QOUmeeuX5y9IvSxXHa6D2A==:17 a=IkcTkHD0fZMA:10 a=Yq5XynenixoA:10 a=x7bEGLp0ZPQA:10 a=VkNPw1HP01LnGYTKEx00:22 a=Da8U98TiO7q1upZEImrf:22 a=Qm0qsxP7aFY2tkT6R2MF:22 a=KmSSIXLuV57r0wwE8Y4A:9 a=QEXdDO2ut3YA:10 a=uxP6HrT_eTzRwkO_Te1X:22 X-Proofpoint-ORIG-GUID: 7sYZl1J7XwvtrMWTgtXWi1tK-NqqqOot X-Proofpoint-Virus-Version: vendor=nai engine=6800 definitions=11740 signatures=596818 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 malwarescore=0 spamscore=0 priorityscore=1501 clxscore=1015 impostorscore=10 bulkscore=10 adultscore=0 phishscore=0 lowpriorityscore=10 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2603050001 definitions=main-2603250142 X-Rspam-User: X-Rspamd-Queue-Id: AF0FFC0011 X-Stat-Signature: ceik4b9edx97xn5r1nk7xjr49xnffg91 X-Rspamd-Server: rspam06 X-HE-Tag: 1774467044-913534 X-HE-Meta: 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 JgQMRnYH IdDOgJpsuS7Yiu1W2hYb5g+379bTDOLZ+EGrCbx79mSEa5TssUltCFqHMDsZE49DB0bi97v3BpfnfmAAcVl93EXdQ+ljQ047Z74pqLOfIfI1zIJjfq6EXB+LZhZeRPo/jVRASQCRPOIjkj2BSzb2gDPu59jXw2QJUf+WReW1gA2skwI2PnJAYNGyMqYBezRosIHXCdERd8niLWf2xMGwts8evvqm0OCIM5Iphkd32PTt2fyKywnVrh3ZEh4IOlGRBqudZvNMrR9skRRnR2sLxymh5OAUrer+ISTSOqWONBUe/XzYnkfz6ZrBcHjfhCc9S0w/bEjU3FFtWdeFDfCyTFD+BIQ1qF8kiTNb8WREHDTE9RHR3eQPQuTsWxbl4nz8EXmK42ZAyu/AlwbvRSWyZ1wkvL76P2bL64+enEovZt28bLHlIOQ+DshAtFxT0R2XBbg5Q0/xGpwW5dxYPV7qydwE58QsIJ6mfxCC4E3rNUyy1yyU= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Block device buffered reads and writes already pass through filemap_read() and iomap_file_buffered_write() respectively, both of which handle IOCB_DONTCACHE. Enable RWF_DONTCACHE for block device files by setting FOP_DONTCACHE in def_blk_fops. For CONFIG_BUFFER_HEAD=y paths, add block_write_begin_iocb() which threads the kiocb through so that buffer_head-based I/O can use DONTCACHE behavior. The existing block_write_begin() is preserved as a wrapper that passes a NULL iocb. Set BIO_COMPLETE_IN_TASK in submit_bh_wbc() when the folio has dropbehind so that buffer_head writeback completions get deferred to task context. CONFIG_BUFFER_HEAD=n paths are handled by the previously added iomap BIO_COMPLETE_IN_TASK support. This support is useful for databases that operate on raw block devices, among other userspace applications. Signed-off-by: Tal Zussman --- block/fops.c | 5 +++-- fs/buffer.c | 22 +++++++++++++++++++--- include/linux/buffer_head.h | 3 +++ 3 files changed, 25 insertions(+), 5 deletions(-) diff --git a/block/fops.c b/block/fops.c index 4d32785b31d9..d8165f6ba71c 100644 --- a/block/fops.c +++ b/block/fops.c @@ -505,7 +505,8 @@ static int blkdev_write_begin(const struct kiocb *iocb, unsigned len, struct folio **foliop, void **fsdata) { - return block_write_begin(mapping, pos, len, foliop, blkdev_get_block); + return block_write_begin_iocb(iocb, mapping, pos, len, foliop, + blkdev_get_block); } static int blkdev_write_end(const struct kiocb *iocb, @@ -967,7 +968,7 @@ const struct file_operations def_blk_fops = { .splice_write = iter_file_splice_write, .fallocate = blkdev_fallocate, .uring_cmd = blkdev_uring_cmd, - .fop_flags = FOP_BUFFER_RASYNC, + .fop_flags = FOP_BUFFER_RASYNC | FOP_DONTCACHE, }; static __init int blkdev_init(void) diff --git a/fs/buffer.c b/fs/buffer.c index ed724a902657..c60c0ad6cc35 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -2239,14 +2239,19 @@ EXPORT_SYMBOL(block_commit_write); * * The filesystem needs to handle block truncation upon failure. */ -int block_write_begin(struct address_space *mapping, loff_t pos, unsigned len, +int block_write_begin_iocb(const struct kiocb *iocb, + struct address_space *mapping, loff_t pos, unsigned len, struct folio **foliop, get_block_t *get_block) { pgoff_t index = pos >> PAGE_SHIFT; + fgf_t fgp_flags = FGP_WRITEBEGIN; struct folio *folio; int status; - folio = __filemap_get_folio(mapping, index, FGP_WRITEBEGIN, + if (iocb && iocb->ki_flags & IOCB_DONTCACHE) + fgp_flags |= FGP_DONTCACHE; + + folio = __filemap_get_folio(mapping, index, fgp_flags, mapping_gfp_mask(mapping)); if (IS_ERR(folio)) return PTR_ERR(folio); @@ -2261,6 +2266,13 @@ int block_write_begin(struct address_space *mapping, loff_t pos, unsigned len, *foliop = folio; return status; } + +int block_write_begin(struct address_space *mapping, loff_t pos, unsigned len, + struct folio **foliop, get_block_t *get_block) +{ + return block_write_begin_iocb(NULL, mapping, pos, len, foliop, + get_block); +} EXPORT_SYMBOL(block_write_begin); int block_write_end(loff_t pos, unsigned len, unsigned copied, @@ -2589,7 +2601,8 @@ int cont_write_begin(const struct kiocb *iocb, struct address_space *mapping, (*bytes)++; } - return block_write_begin(mapping, pos, len, foliop, get_block); + return block_write_begin_iocb(iocb, mapping, pos, len, foliop, + get_block); } EXPORT_SYMBOL(cont_write_begin); @@ -2801,6 +2814,9 @@ static void submit_bh_wbc(blk_opf_t opf, struct buffer_head *bh, bio = bio_alloc(bh->b_bdev, 1, opf, GFP_NOIO); + if (folio_test_dropbehind(bh->b_folio)) + bio_set_flag(bio, BIO_COMPLETE_IN_TASK); + fscrypt_set_bio_crypt_ctx_bh(bio, bh, GFP_NOIO); bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9); diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h index b16b88bfbc3e..ddf88ce290f2 100644 --- a/include/linux/buffer_head.h +++ b/include/linux/buffer_head.h @@ -260,6 +260,9 @@ int block_read_full_folio(struct folio *, get_block_t *); bool block_is_partially_uptodate(struct folio *, size_t from, size_t count); int block_write_begin(struct address_space *mapping, loff_t pos, unsigned len, struct folio **foliop, get_block_t *get_block); +int block_write_begin_iocb(const struct kiocb *iocb, + struct address_space *mapping, loff_t pos, unsigned len, + struct folio **foliop, get_block_t *get_block); int __block_write_begin(struct folio *folio, loff_t pos, unsigned len, get_block_t *get_block); int block_write_end(loff_t pos, unsigned len, unsigned copied, struct folio *); -- 2.39.5