diff options
author | David Howells <dhowells@redhat.com> | 2021-11-02 11:29:55 +0300 |
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committer | Dominique Martinet <asmadeus@codewreck.org> | 2021-11-03 11:45:02 +0300 |
commit | eb497943fa215897f2f60fd28aa6fe52da27ca6c (patch) | |
tree | be3707ed7dff76a33a88a7fbf30562088e3846d9 /fs/9p/vfs_file.c | |
parent | 0dc54bd4d6e03be1f0b678c4297170b79f1a44ab (diff) | |
download | linux-eb497943fa215897f2f60fd28aa6fe52da27ca6c.tar.xz |
9p: Convert to using the netfs helper lib to do reads and caching
Convert the 9p filesystem to use the netfs helper lib to handle readpage,
readahead and write_begin, converting those into a common issue_op for the
filesystem itself to handle. The netfs helper lib also handles reading
from fscache if a cache is available, and interleaving reads from both
sources.
This change also switches from the old fscache I/O API to the new one,
meaning that fscache no longer keeps track of netfs pages and instead does
async DIO between the backing files and the 9p file pagecache. As a part
of this change, the handling of PG_fscache changes. It now just means that
the cache has a write I/O operation in progress on a page (PG_locked
is used for a read I/O op).
Note that this is a cut-down version of the fscache rewrite and does not
change any of the cookie and cache coherency handling.
Changes
=======
ver #4:
- Rebase on top of folios.
- Don't use wait_on_page_bit_killable().
ver #3:
- v9fs_req_issue_op() needs to terminate the subrequest.
- v9fs_write_end() needs to call SetPageUptodate() a bit more often.
- It's not CONFIG_{AFS,V9FS}_FSCACHE[1]
- v9fs_init_rreq() should take a ref on the p9_fid and the cleanup should
drop it [from Dominique Martinet].
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-and-tested-by: Dominique Martinet <asmadeus@codewreck.org>
cc: v9fs-developer@lists.sourceforge.net
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/YUm+xucHxED+1MJp@codewreck.org/ [1]
Link: https://lore.kernel.org/r/163162772646.438332.16323773205855053535.stgit@warthog.procyon.org.uk/ # rfc
Link: https://lore.kernel.org/r/163189109885.2509237.7153668924503399173.stgit@warthog.procyon.org.uk/ # rfc v2
Link: https://lore.kernel.org/r/163363943896.1980952.1226527304649419689.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/163551662876.1877519.14706391695553204156.stgit@warthog.procyon.org.uk/ # v4
Link: https://lore.kernel.org/r/163584179557.4023316.11089762304657644342.stgit@warthog.procyon.org.uk # rebase on folio
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
Diffstat (limited to 'fs/9p/vfs_file.c')
-rw-r--r-- | fs/9p/vfs_file.c | 17 |
1 files changed, 13 insertions, 4 deletions
diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c index 246235ebdb70..8d5e0ef5518e 100644 --- a/fs/9p/vfs_file.c +++ b/fs/9p/vfs_file.c @@ -537,14 +537,23 @@ v9fs_vm_page_mkwrite(struct vm_fault *vmf) p9_debug(P9_DEBUG_VFS, "page %p fid %lx\n", page, (unsigned long)filp->private_data); + v9inode = V9FS_I(inode); + + /* Wait for the page to be written to the cache before we allow it to + * be modified. We then assume the entire page will need writing back. + */ +#ifdef CONFIG_9P_FSCACHE + if (PageFsCache(page) && + wait_on_page_fscache_killable(page) < 0) + return VM_FAULT_RETRY; +#endif + /* Update file times before taking page lock */ file_update_time(filp); - v9inode = V9FS_I(inode); - /* make sure the cache has finished storing the page */ - v9fs_fscache_wait_on_page_write(inode, page); BUG_ON(!v9inode->writeback_fid); - lock_page(page); + if (lock_page_killable(page) < 0) + return VM_FAULT_RETRY; if (page->mapping != inode->i_mapping) goto out_unlock; wait_for_stable_page(page); |