diff options
author | Darrick J. Wong <djwong@kernel.org> | 2023-08-10 17:48:05 +0300 |
---|---|---|
committer | Darrick J. Wong <djwong@kernel.org> | 2023-08-10 17:48:05 +0300 |
commit | 137db333b29186ad085d593c8a702e9f0e9c43f4 (patch) | |
tree | a818a18d232013ad80e93c123aee651a6d2f3e33 /fs/xfs | |
parent | c390c6450318345b3caa1996a4ef1367477a5aa8 (diff) | |
download | linux-137db333b29186ad085d593c8a702e9f0e9c43f4.tar.xz |
xfs: teach xfile to pass back direct-map pages to caller
Certain xfile array operations (such as sorting) can be sped up quite a
bit by allowing xfile users to grab a page to bulk-read the records
contained within it. Create helper methods to facilitate this.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Kent Overstreet <kent.overstreet@linux.dev>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Diffstat (limited to 'fs/xfs')
-rw-r--r-- | fs/xfs/scrub/trace.h | 2 | ||||
-rw-r--r-- | fs/xfs/scrub/xfile.c | 108 | ||||
-rw-r--r-- | fs/xfs/scrub/xfile.h | 10 |
3 files changed, 120 insertions, 0 deletions
diff --git a/fs/xfs/scrub/trace.h b/fs/xfs/scrub/trace.h index e95c16767f78..c2e611e2af49 100644 --- a/fs/xfs/scrub/trace.h +++ b/fs/xfs/scrub/trace.h @@ -821,6 +821,8 @@ DEFINE_EVENT(xfile_class, name, \ DEFINE_XFILE_EVENT(xfile_pread); DEFINE_XFILE_EVENT(xfile_pwrite); DEFINE_XFILE_EVENT(xfile_seek_data); +DEFINE_XFILE_EVENT(xfile_get_page); +DEFINE_XFILE_EVENT(xfile_put_page); TRACE_EVENT(xfarray_create, TP_PROTO(struct xfarray *xfa, unsigned long long required_capacity), diff --git a/fs/xfs/scrub/xfile.c b/fs/xfs/scrub/xfile.c index 19d512887980..d98e8e77c684 100644 --- a/fs/xfs/scrub/xfile.c +++ b/fs/xfs/scrub/xfile.c @@ -310,3 +310,111 @@ xfile_stat( statbuf->bytes = ks.blocks << SECTOR_SHIFT; return 0; } + +/* + * Grab the (locked) page for a memory object. The object cannot span a page + * boundary. Returns 0 (and a locked page) if successful, -ENOTBLK if we + * cannot grab the page, or the usual negative errno. + */ +int +xfile_get_page( + struct xfile *xf, + loff_t pos, + unsigned int len, + struct xfile_page *xfpage) +{ + struct inode *inode = file_inode(xf->file); + struct address_space *mapping = inode->i_mapping; + const struct address_space_operations *aops = mapping->a_ops; + struct page *page = NULL; + void *fsdata = NULL; + loff_t key = round_down(pos, PAGE_SIZE); + unsigned int pflags; + int error; + + if (inode->i_sb->s_maxbytes - pos < len) + return -ENOMEM; + if (len > PAGE_SIZE - offset_in_page(pos)) + return -ENOTBLK; + + trace_xfile_get_page(xf, pos, len); + + pflags = memalloc_nofs_save(); + + /* + * We call write_begin directly here to avoid all the freezer + * protection lock-taking that happens in the normal path. shmem + * doesn't support fs freeze, but lockdep doesn't know that and will + * trip over that. + */ + error = aops->write_begin(NULL, mapping, key, PAGE_SIZE, &page, + &fsdata); + if (error) + goto out_pflags; + + /* We got the page, so make sure we push out EOF. */ + if (i_size_read(inode) < pos + len) + i_size_write(inode, pos + len); + + /* + * If the page isn't up to date, fill it with zeroes before we hand it + * to the caller and make sure the backing store will hold on to them. + */ + if (!PageUptodate(page)) { + void *kaddr; + + kaddr = kmap_local_page(page); + memset(kaddr, 0, PAGE_SIZE); + kunmap_local(kaddr); + SetPageUptodate(page); + } + + /* + * Mark each page dirty so that the contents are written to some + * backing store when we drop this buffer, and take an extra reference + * to prevent the xfile page from being swapped or removed from the + * page cache by reclaim if the caller unlocks the page. + */ + set_page_dirty(page); + get_page(page); + + xfpage->page = page; + xfpage->fsdata = fsdata; + xfpage->pos = key; +out_pflags: + memalloc_nofs_restore(pflags); + return error; +} + +/* + * Release the (locked) page for a memory object. Returns 0 or a negative + * errno. + */ +int +xfile_put_page( + struct xfile *xf, + struct xfile_page *xfpage) +{ + struct inode *inode = file_inode(xf->file); + struct address_space *mapping = inode->i_mapping; + const struct address_space_operations *aops = mapping->a_ops; + unsigned int pflags; + int ret; + + trace_xfile_put_page(xf, xfpage->pos, PAGE_SIZE); + + /* Give back the reference that we took in xfile_get_page. */ + put_page(xfpage->page); + + pflags = memalloc_nofs_save(); + ret = aops->write_end(NULL, mapping, xfpage->pos, PAGE_SIZE, PAGE_SIZE, + xfpage->page, xfpage->fsdata); + memalloc_nofs_restore(pflags); + memset(xfpage, 0, sizeof(struct xfile_page)); + + if (ret < 0) + return ret; + if (ret != PAGE_SIZE) + return -EIO; + return 0; +} diff --git a/fs/xfs/scrub/xfile.h b/fs/xfs/scrub/xfile.h index 9328a37fedaa..7065abd97a9a 100644 --- a/fs/xfs/scrub/xfile.h +++ b/fs/xfs/scrub/xfile.h @@ -6,6 +6,12 @@ #ifndef __XFS_SCRUB_XFILE_H__ #define __XFS_SCRUB_XFILE_H__ +struct xfile_page { + struct page *page; + void *fsdata; + loff_t pos; +}; + struct xfile { struct file *file; }; @@ -54,4 +60,8 @@ struct xfile_stat { int xfile_stat(struct xfile *xf, struct xfile_stat *statbuf); +int xfile_get_page(struct xfile *xf, loff_t offset, unsigned int len, + struct xfile_page *xbuf); +int xfile_put_page(struct xfile *xf, struct xfile_page *xbuf); + #endif /* __XFS_SCRUB_XFILE_H__ */ |