| Message ID | 20210730194625.93856-2-hsiangkao@linux.alibaba.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | erofs: iomap support for uncompressed cases | expand |
On 2021/7/31 3:46, Gao Xiang wrote: > From: Huang Jianan <huangjianan@oppo.com> > > Add iomap support for non-tailpacking uncompressed data in order to > support DIO and DAX. > > Direct I/O is useful in certain scenarios for uncompressed files. > For example, double pagecache can be avoid by direct I/O when > loop device is used for uncompressed files containing upper layer > compressed filesystem. > > This adds iomap DIO support for non-tailpacking cases first and > tail-packing inline files are handled in the follow-up patch. > > Cc: linux-fsdevel@vger.kernel.org > Signed-off-by: Huang Jianan <huangjianan@oppo.com> > Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> > --- > fs/erofs/Kconfig | 1 + > fs/erofs/data.c | 102 ++++++++++++++++++++++++++++++++++++++++++++ > fs/erofs/inode.c | 5 ++- > fs/erofs/internal.h | 1 + > 4 files changed, 108 insertions(+), 1 deletion(-) > > diff --git a/fs/erofs/Kconfig b/fs/erofs/Kconfig > index 906af0c1998c..14b747026742 100644 > --- a/fs/erofs/Kconfig > +++ b/fs/erofs/Kconfig > @@ -3,6 +3,7 @@ > config EROFS_FS > tristate "EROFS filesystem support" > depends on BLOCK > + select FS_IOMAP > select LIBCRC32C > help > EROFS (Enhanced Read-Only File System) is a lightweight > diff --git a/fs/erofs/data.c b/fs/erofs/data.c > index 3787a5fb0a42..1f97151a9f90 100644 > --- a/fs/erofs/data.c > +++ b/fs/erofs/data.c > @@ -5,6 +5,7 @@ > */ > #include "internal.h" > #include <linux/prefetch.h> > +#include <linux/iomap.h> > > #include <trace/events/erofs.h> > > @@ -308,9 +309,110 @@ static sector_t erofs_bmap(struct address_space *mapping, sector_t block) > return 0; > } > > +static int erofs_iomap_begin(struct inode *inode, loff_t offset, loff_t length, > + unsigned int flags, struct iomap *iomap, struct iomap *srcmap) > +{ > + int ret; > + struct erofs_map_blocks map; > + > + map.m_la = offset; > + map.m_llen = length; > + > + ret = erofs_map_blocks_flatmode(inode, &map, EROFS_GET_BLOCKS_RAW); > + if (ret < 0) > + return ret; > + > + iomap->bdev = inode->i_sb->s_bdev; > + iomap->offset = map.m_la; > + iomap->length = map.m_llen; > + iomap->flags = 0; > + > + if (!(map.m_flags & EROFS_MAP_MAPPED)) { > + iomap->type = IOMAP_HOLE; > + iomap->addr = IOMAP_NULL_ADDR; > + if (!iomap->length) > + iomap->length = length; This only happens for the case offset exceeds isize? > + return 0; > + } > + > + /* that shouldn't happen for now */ > + if (map.m_flags & EROFS_MAP_META) { > + DBG_BUGON(1); > + return -ENOTBLK; > + } > + iomap->type = IOMAP_MAPPED; > + iomap->addr = map.m_pa; > + return 0; > +} > + > +const struct iomap_ops erofs_iomap_ops = { > + .iomap_begin = erofs_iomap_begin, > +}; > + > +static int erofs_prepare_dio(struct kiocb *iocb, struct iov_iter *to) > +{ > + struct inode *inode = file_inode(iocb->ki_filp); > + loff_t align = iocb->ki_pos | iov_iter_count(to) | > + iov_iter_alignment(to); > + struct block_device *bdev = inode->i_sb->s_bdev; > + unsigned int blksize_mask; > + > + if (bdev) > + blksize_mask = (1 << ilog2(bdev_logical_block_size(bdev))) - 1; > + else > + blksize_mask = (1 << inode->i_blkbits) - 1; > + > + if (align & blksize_mask) > + return -EINVAL; > + > + /* > + * Temporarily fall back tail-packing inline to buffered I/O instead > + * since tail-packing inline support relies on an iomap core update. > + */ > + if (EROFS_I(inode)->datalayout == EROFS_INODE_FLAT_INLINE && > + iocb->ki_pos + iov_iter_count(to) > > + rounddown(inode->i_size, EROFS_BLKSIZ)) > + return 1; > + return 0; > +} > + > +static ssize_t erofs_file_read_iter(struct kiocb *iocb, struct iov_iter *to) > +{ > + /* no need taking (shared) inode lock since it's a ro filesystem */ > + if (!iov_iter_count(to)) > + return 0; > + > + if (iocb->ki_flags & IOCB_DIRECT) { > + int err = erofs_prepare_dio(iocb, to); > + > + if (!err) > + return iomap_dio_rw(iocb, to, &erofs_iomap_ops, > + NULL, 0); > + if (err < 0) > + return err; > + /* > + * Fallback to buffered I/O if the operation being performed on > + * the inode is not supported by direct I/O. The IOCB_DIRECT > + * flag needs to be cleared here in order to ensure that the > + * direct I/O path within generic_file_read_iter() is not > + * taken. > + */ > + iocb->ki_flags &= ~IOCB_DIRECT; > + } > + return generic_file_read_iter(iocb, to); It looks it's fine to call filemap_read() directly since above codes have covered DIO case, then we don't need to change iocb->ki_flags flag, it's minor though. > +} > + > /* for uncompressed (aligned) files and raw access for other files */ > const struct address_space_operations erofs_raw_access_aops = { > .readpage = erofs_raw_access_readpage, > .readahead = erofs_raw_access_readahead, > .bmap = erofs_bmap, > + .direct_IO = noop_direct_IO, > +}; > + > +const struct file_operations erofs_file_fops = { > + .llseek = generic_file_llseek, > + .read_iter = erofs_file_read_iter, > + .mmap = generic_file_readonly_mmap, > + .splice_read = generic_file_splice_read, > }; > diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c > index aa8a0d770ba3..00edb7562fea 100644 > --- a/fs/erofs/inode.c > +++ b/fs/erofs/inode.c > @@ -247,7 +247,10 @@ static int erofs_fill_inode(struct inode *inode, int isdir) > switch (inode->i_mode & S_IFMT) { > case S_IFREG: > inode->i_op = &erofs_generic_iops; > - inode->i_fop = &generic_ro_fops; > + if (!erofs_inode_is_data_compressed(vi->datalayout)) > + inode->i_fop = &erofs_file_fops; > + else > + inode->i_fop = &generic_ro_fops; if (erofs_inode_is_data_compressed(vi->datalayout)) inode->i_fop = &generic_ro_fops; else inode->i_fop = &erofs_file_fops; Otherwise, it looks good to me. Reviewed-by: Chao Yu <chao@kernel.org> Thanks > break; > case S_IFDIR: > inode->i_op = &erofs_dir_iops; > diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h > index 543c2ff97d30..2669c785d548 100644 > --- a/fs/erofs/internal.h > +++ b/fs/erofs/internal.h > @@ -371,6 +371,7 @@ static inline int z_erofs_map_blocks_iter(struct inode *inode, > #endif /* !CONFIG_EROFS_FS_ZIP */ > > /* data.c */ > +extern const struct file_operations erofs_file_fops; > struct page *erofs_get_meta_page(struct super_block *sb, erofs_blk_t blkaddr); > > /* inode.c */ >
Hi Chao, On Wed, Aug 04, 2021 at 10:57:08AM +0800, Chao Yu wrote: > On 2021/7/31 3:46, Gao Xiang wrote: ... > > } > > +static int erofs_iomap_begin(struct inode *inode, loff_t offset, loff_t length, > > + unsigned int flags, struct iomap *iomap, struct iomap *srcmap) > > +{ > > + int ret; > > + struct erofs_map_blocks map; > > + > > + map.m_la = offset; > > + map.m_llen = length; > > + > > + ret = erofs_map_blocks_flatmode(inode, &map, EROFS_GET_BLOCKS_RAW); > > + if (ret < 0) > > + return ret; > > + > > + iomap->bdev = inode->i_sb->s_bdev; > > + iomap->offset = map.m_la; > > + iomap->length = map.m_llen; > > + iomap->flags = 0; > > + > > + if (!(map.m_flags & EROFS_MAP_MAPPED)) { > > + iomap->type = IOMAP_HOLE; > > + iomap->addr = IOMAP_NULL_ADDR; > > + if (!iomap->length) > > + iomap->length = length; > > This only happens for the case offset exceeds isize? Thanks for the review. Yeah, this is a convention (length 0 with !EROFS_MAP_MAPPED) for post-EOF in erofs_map_blocks_flatmode(), need to follow iomap rule as well. > > > + return 0; > > + } > > + > > + /* that shouldn't happen for now */ > > + if (map.m_flags & EROFS_MAP_META) { > > + DBG_BUGON(1); > > + return -ENOTBLK; > > + } > > + iomap->type = IOMAP_MAPPED; > > + iomap->addr = map.m_pa; > > + return 0; > > +} > > + > > +const struct iomap_ops erofs_iomap_ops = { > > + .iomap_begin = erofs_iomap_begin, > > +}; > > + > > +static int erofs_prepare_dio(struct kiocb *iocb, struct iov_iter *to) > > +{ > > + struct inode *inode = file_inode(iocb->ki_filp); > > + loff_t align = iocb->ki_pos | iov_iter_count(to) | > > + iov_iter_alignment(to); > > + struct block_device *bdev = inode->i_sb->s_bdev; > > + unsigned int blksize_mask; > > + > > + if (bdev) > > + blksize_mask = (1 << ilog2(bdev_logical_block_size(bdev))) - 1; > > + else > > + blksize_mask = (1 << inode->i_blkbits) - 1; > > + > > + if (align & blksize_mask) > > + return -EINVAL; > > + > > + /* > > + * Temporarily fall back tail-packing inline to buffered I/O instead > > + * since tail-packing inline support relies on an iomap core update. > > + */ > > + if (EROFS_I(inode)->datalayout == EROFS_INODE_FLAT_INLINE && > > + iocb->ki_pos + iov_iter_count(to) > > > + rounddown(inode->i_size, EROFS_BLKSIZ)) > > + return 1; > > + return 0; > > +} > > + > > +static ssize_t erofs_file_read_iter(struct kiocb *iocb, struct iov_iter *to) > > +{ > > + /* no need taking (shared) inode lock since it's a ro filesystem */ > > + if (!iov_iter_count(to)) > > + return 0; > > + > > + if (iocb->ki_flags & IOCB_DIRECT) { > > + int err = erofs_prepare_dio(iocb, to); > > + > > + if (!err) > > + return iomap_dio_rw(iocb, to, &erofs_iomap_ops, > > + NULL, 0); > > + if (err < 0) > > + return err; > > + /* > > + * Fallback to buffered I/O if the operation being performed on > > + * the inode is not supported by direct I/O. The IOCB_DIRECT > > + * flag needs to be cleared here in order to ensure that the > > + * direct I/O path within generic_file_read_iter() is not > > + * taken. > > + */ > > + iocb->ki_flags &= ~IOCB_DIRECT; > > + } > > + return generic_file_read_iter(iocb, to); > > It looks it's fine to call filemap_read() directly since above codes have > covered DIO case, then we don't need to change iocb->ki_flags flag, it's > minor though. Yeah, we could use filemap_read() here instead. yet IMO, it might be better to drop IOCB_DIRECT too to keep iocb consistent with the real semantics (even it's not used internally.) > > > +} > > + > > /* for uncompressed (aligned) files and raw access for other files */ > > const struct address_space_operations erofs_raw_access_aops = { > > .readpage = erofs_raw_access_readpage, > > .readahead = erofs_raw_access_readahead, > > .bmap = erofs_bmap, > > + .direct_IO = noop_direct_IO, > > +}; > > + > > +const struct file_operations erofs_file_fops = { > > + .llseek = generic_file_llseek, > > + .read_iter = erofs_file_read_iter, > > + .mmap = generic_file_readonly_mmap, > > + .splice_read = generic_file_splice_read, > > }; > > diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c > > index aa8a0d770ba3..00edb7562fea 100644 > > --- a/fs/erofs/inode.c > > +++ b/fs/erofs/inode.c > > @@ -247,7 +247,10 @@ static int erofs_fill_inode(struct inode *inode, int isdir) > > switch (inode->i_mode & S_IFMT) { > > case S_IFREG: > > inode->i_op = &erofs_generic_iops; > > - inode->i_fop = &generic_ro_fops; > > + if (!erofs_inode_is_data_compressed(vi->datalayout)) > > + inode->i_fop = &erofs_file_fops; > > + else > > + inode->i_fop = &generic_ro_fops; > > if (erofs_inode_is_data_compressed(vi->datalayout)) > inode->i_fop = &generic_ro_fops; > else > inode->i_fop = &erofs_file_fops; > > Otherwise, it looks good to me. ok, will fix in the next version. Thanks, Gao Xiang > > Reviewed-by: Chao Yu <chao@kernel.org> > > Thanks > > > break; > > case S_IFDIR: > > inode->i_op = &erofs_dir_iops; > > diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h > > index 543c2ff97d30..2669c785d548 100644 > > --- a/fs/erofs/internal.h > > +++ b/fs/erofs/internal.h > > @@ -371,6 +371,7 @@ static inline int z_erofs_map_blocks_iter(struct inode *inode, > > #endif /* !CONFIG_EROFS_FS_ZIP */ > > /* data.c */ > > +extern const struct file_operations erofs_file_fops; > > struct page *erofs_get_meta_page(struct super_block *sb, erofs_blk_t blkaddr); > > /* inode.c */ > >
On Wed, Aug 04, 2021 at 12:30:35PM +0800, Gao Xiang wrote: > Hi Chao, > > On Wed, Aug 04, 2021 at 10:57:08AM +0800, Chao Yu wrote: > > On 2021/7/31 3:46, Gao Xiang wrote: > > ... > > > > } > > > +static int erofs_iomap_begin(struct inode *inode, loff_t offset, loff_t length, > > > + unsigned int flags, struct iomap *iomap, struct iomap *srcmap) > > > +{ > > > + int ret; > > > + struct erofs_map_blocks map; > > > + > > > + map.m_la = offset; > > > + map.m_llen = length; > > > + > > > + ret = erofs_map_blocks_flatmode(inode, &map, EROFS_GET_BLOCKS_RAW); > > > + if (ret < 0) > > > + return ret; > > > + > > > + iomap->bdev = inode->i_sb->s_bdev; > > > + iomap->offset = map.m_la; > > > + iomap->length = map.m_llen; > > > + iomap->flags = 0; > > > + > > > + if (!(map.m_flags & EROFS_MAP_MAPPED)) { > > > + iomap->type = IOMAP_HOLE; > > > + iomap->addr = IOMAP_NULL_ADDR; > > > + if (!iomap->length) > > > + iomap->length = length; > > > > This only happens for the case offset exceeds isize? > > Thanks for the review. > > Yeah, this is a convention (length 0 with !EROFS_MAP_MAPPED) for post-EOF > in erofs_map_blocks_flatmode(), need to follow iomap rule as well. > > > > > > + return 0; > > > + } > > > + > > > + /* that shouldn't happen for now */ > > > + if (map.m_flags & EROFS_MAP_META) { > > > + DBG_BUGON(1); > > > + return -ENOTBLK; > > > + } > > > + iomap->type = IOMAP_MAPPED; > > > + iomap->addr = map.m_pa; > > > + return 0; > > > +} > > > + > > > +const struct iomap_ops erofs_iomap_ops = { > > > + .iomap_begin = erofs_iomap_begin, > > > +}; > > > + > > > +static int erofs_prepare_dio(struct kiocb *iocb, struct iov_iter *to) > > > +{ > > > + struct inode *inode = file_inode(iocb->ki_filp); > > > + loff_t align = iocb->ki_pos | iov_iter_count(to) | > > > + iov_iter_alignment(to); > > > + struct block_device *bdev = inode->i_sb->s_bdev; > > > + unsigned int blksize_mask; > > > + > > > + if (bdev) > > > + blksize_mask = (1 << ilog2(bdev_logical_block_size(bdev))) - 1; > > > + else > > > + blksize_mask = (1 << inode->i_blkbits) - 1; > > > + > > > + if (align & blksize_mask) > > > + return -EINVAL; > > > + > > > + /* > > > + * Temporarily fall back tail-packing inline to buffered I/O instead > > > + * since tail-packing inline support relies on an iomap core update. > > > + */ > > > + if (EROFS_I(inode)->datalayout == EROFS_INODE_FLAT_INLINE && > > > + iocb->ki_pos + iov_iter_count(to) > > > > + rounddown(inode->i_size, EROFS_BLKSIZ)) > > > + return 1; > > > + return 0; > > > +} > > > + > > > +static ssize_t erofs_file_read_iter(struct kiocb *iocb, struct iov_iter *to) > > > +{ > > > + /* no need taking (shared) inode lock since it's a ro filesystem */ > > > + if (!iov_iter_count(to)) > > > + return 0; > > > + > > > + if (iocb->ki_flags & IOCB_DIRECT) { > > > + int err = erofs_prepare_dio(iocb, to); > > > + > > > + if (!err) > > > + return iomap_dio_rw(iocb, to, &erofs_iomap_ops, > > > + NULL, 0); > > > + if (err < 0) > > > + return err; > > > + /* > > > + * Fallback to buffered I/O if the operation being performed on > > > + * the inode is not supported by direct I/O. The IOCB_DIRECT > > > + * flag needs to be cleared here in order to ensure that the > > > + * direct I/O path within generic_file_read_iter() is not > > > + * taken. > > > + */ > > > + iocb->ki_flags &= ~IOCB_DIRECT; > > > + } > > > + return generic_file_read_iter(iocb, to); > > > > It looks it's fine to call filemap_read() directly since above codes have > > covered DIO case, then we don't need to change iocb->ki_flags flag, it's > > minor though. > > Yeah, we could use filemap_read() here instead. yet IMO, it might be > better to drop IOCB_DIRECT too to keep iocb consistent with the real > semantics (even it's not used internally.) After checking the other users of filemap_read(), I'm fine to leave IOCB_DIRECT as-is. Will update. Thanks, Gao Xiang
diff --git a/fs/erofs/Kconfig b/fs/erofs/Kconfig index 906af0c1998c..14b747026742 100644 --- a/fs/erofs/Kconfig +++ b/fs/erofs/Kconfig @@ -3,6 +3,7 @@ config EROFS_FS tristate "EROFS filesystem support" depends on BLOCK + select FS_IOMAP select LIBCRC32C help EROFS (Enhanced Read-Only File System) is a lightweight diff --git a/fs/erofs/data.c b/fs/erofs/data.c index 3787a5fb0a42..1f97151a9f90 100644 --- a/fs/erofs/data.c +++ b/fs/erofs/data.c @@ -5,6 +5,7 @@ */ #include "internal.h" #include <linux/prefetch.h> +#include <linux/iomap.h> #include <trace/events/erofs.h> @@ -308,9 +309,110 @@ static sector_t erofs_bmap(struct address_space *mapping, sector_t block) return 0; } +static int erofs_iomap_begin(struct inode *inode, loff_t offset, loff_t length, + unsigned int flags, struct iomap *iomap, struct iomap *srcmap) +{ + int ret; + struct erofs_map_blocks map; + + map.m_la = offset; + map.m_llen = length; + + ret = erofs_map_blocks_flatmode(inode, &map, EROFS_GET_BLOCKS_RAW); + if (ret < 0) + return ret; + + iomap->bdev = inode->i_sb->s_bdev; + iomap->offset = map.m_la; + iomap->length = map.m_llen; + iomap->flags = 0; + + if (!(map.m_flags & EROFS_MAP_MAPPED)) { + iomap->type = IOMAP_HOLE; + iomap->addr = IOMAP_NULL_ADDR; + if (!iomap->length) + iomap->length = length; + return 0; + } + + /* that shouldn't happen for now */ + if (map.m_flags & EROFS_MAP_META) { + DBG_BUGON(1); + return -ENOTBLK; + } + iomap->type = IOMAP_MAPPED; + iomap->addr = map.m_pa; + return 0; +} + +const struct iomap_ops erofs_iomap_ops = { + .iomap_begin = erofs_iomap_begin, +}; + +static int erofs_prepare_dio(struct kiocb *iocb, struct iov_iter *to) +{ + struct inode *inode = file_inode(iocb->ki_filp); + loff_t align = iocb->ki_pos | iov_iter_count(to) | + iov_iter_alignment(to); + struct block_device *bdev = inode->i_sb->s_bdev; + unsigned int blksize_mask; + + if (bdev) + blksize_mask = (1 << ilog2(bdev_logical_block_size(bdev))) - 1; + else + blksize_mask = (1 << inode->i_blkbits) - 1; + + if (align & blksize_mask) + return -EINVAL; + + /* + * Temporarily fall back tail-packing inline to buffered I/O instead + * since tail-packing inline support relies on an iomap core update. + */ + if (EROFS_I(inode)->datalayout == EROFS_INODE_FLAT_INLINE && + iocb->ki_pos + iov_iter_count(to) > + rounddown(inode->i_size, EROFS_BLKSIZ)) + return 1; + return 0; +} + +static ssize_t erofs_file_read_iter(struct kiocb *iocb, struct iov_iter *to) +{ + /* no need taking (shared) inode lock since it's a ro filesystem */ + if (!iov_iter_count(to)) + return 0; + + if (iocb->ki_flags & IOCB_DIRECT) { + int err = erofs_prepare_dio(iocb, to); + + if (!err) + return iomap_dio_rw(iocb, to, &erofs_iomap_ops, + NULL, 0); + if (err < 0) + return err; + /* + * Fallback to buffered I/O if the operation being performed on + * the inode is not supported by direct I/O. The IOCB_DIRECT + * flag needs to be cleared here in order to ensure that the + * direct I/O path within generic_file_read_iter() is not + * taken. + */ + iocb->ki_flags &= ~IOCB_DIRECT; + } + return generic_file_read_iter(iocb, to); +} + /* for uncompressed (aligned) files and raw access for other files */ const struct address_space_operations erofs_raw_access_aops = { .readpage = erofs_raw_access_readpage, .readahead = erofs_raw_access_readahead, .bmap = erofs_bmap, + .direct_IO = noop_direct_IO, +}; + +const struct file_operations erofs_file_fops = { + .llseek = generic_file_llseek, + .read_iter = erofs_file_read_iter, + .mmap = generic_file_readonly_mmap, + .splice_read = generic_file_splice_read, }; diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c index aa8a0d770ba3..00edb7562fea 100644 --- a/fs/erofs/inode.c +++ b/fs/erofs/inode.c @@ -247,7 +247,10 @@ static int erofs_fill_inode(struct inode *inode, int isdir) switch (inode->i_mode & S_IFMT) { case S_IFREG: inode->i_op = &erofs_generic_iops; - inode->i_fop = &generic_ro_fops; + if (!erofs_inode_is_data_compressed(vi->datalayout)) + inode->i_fop = &erofs_file_fops; + else + inode->i_fop = &generic_ro_fops; break; case S_IFDIR: inode->i_op = &erofs_dir_iops; diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h index 543c2ff97d30..2669c785d548 100644 --- a/fs/erofs/internal.h +++ b/fs/erofs/internal.h @@ -371,6 +371,7 @@ static inline int z_erofs_map_blocks_iter(struct inode *inode, #endif /* !CONFIG_EROFS_FS_ZIP */ /* data.c */ +extern const struct file_operations erofs_file_fops; struct page *erofs_get_meta_page(struct super_block *sb, erofs_blk_t blkaddr); /* inode.c */