summaryrefslogtreecommitdiff
path: root/fs/ext4/move_extent.c
diff options
context:
space:
mode:
authorDavid Howells <dhowells@redhat.com>2023-06-28 13:48:51 +0300
committerAndrew Morton <akpm@linux-foundation.org>2023-08-18 20:12:12 +0300
commit0201ebf274a306a6ebb95e5dc2d6a0a27c737cac (patch)
treef419d3eba3454f01be5f2be92697d796af49bccd /fs/ext4/move_extent.c
parentdba438bd7663fefab870a6dd4b01ed0923c32d79 (diff)
downloadlinux-0201ebf274a306a6ebb95e5dc2d6a0a27c737cac.tar.xz
mm: merge folio_has_private()/filemap_release_folio() call pairs
Patch series "mm, netfs, fscache: Stop read optimisation when folio removed from pagecache", v7. This fixes an optimisation in fscache whereby we don't read from the cache for a particular file until we know that there's data there that we don't have in the pagecache. The problem is that I'm no longer using PG_fscache (aka PG_private_2) to indicate that the page is cached and so I don't get a notification when a cached page is dropped from the pagecache. The first patch merges some folio_has_private() and filemap_release_folio() pairs and introduces a helper, folio_needs_release(), to indicate if a release is required. The second patch is the actual fix. Following Willy's suggestions[1], it adds an AS_RELEASE_ALWAYS flag to an address_space that will make filemap_release_folio() always call ->release_folio(), even if PG_private/PG_private_2 aren't set. folio_needs_release() is altered to add a check for this. This patch (of 2): Make filemap_release_folio() check folio_has_private(). Then, in most cases, where a call to folio_has_private() is immediately followed by a call to filemap_release_folio(), we can get rid of the test in the pair. There are a couple of sites in mm/vscan.c that this can't so easily be done. In shrink_folio_list(), there are actually three cases (something different is done for incompletely invalidated buffers), but filemap_release_folio() elides two of them. In shrink_active_list(), we don't have have the folio lock yet, so the check allows us to avoid locking the page unnecessarily. A wrapper function to check if a folio needs release is provided for those places that still need to do it in the mm/ directory. This will acquire additional parts to the condition in a future patch. After this, the only remaining caller of folio_has_private() outside of mm/ is a check in fuse. Link: https://lkml.kernel.org/r/20230628104852.3391651-1-dhowells@redhat.com Link: https://lkml.kernel.org/r/20230628104852.3391651-2-dhowells@redhat.com Reported-by: Rohith Surabattula <rohiths.msft@gmail.com> Suggested-by: Matthew Wilcox <willy@infradead.org> Signed-off-by: David Howells <dhowells@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Steve French <sfrench@samba.org> Cc: Shyam Prasad N <nspmangalore@gmail.com> Cc: Rohith Surabattula <rohiths.msft@gmail.com> Cc: Dave Wysochanski <dwysocha@redhat.com> Cc: Dominique Martinet <asmadeus@codewreck.org> Cc: Ilya Dryomov <idryomov@gmail.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Xiubo Li <xiubli@redhat.com> Cc: Jingbo Xu <jefflexu@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'fs/ext4/move_extent.c')
-rw-r--r--fs/ext4/move_extent.c12
1 files changed, 4 insertions, 8 deletions
diff --git a/fs/ext4/move_extent.c b/fs/ext4/move_extent.c
index f4b4861a74ee..18a9e7c47975 100644
--- a/fs/ext4/move_extent.c
+++ b/fs/ext4/move_extent.c
@@ -340,10 +340,8 @@ again:
ext4_double_up_write_data_sem(orig_inode, donor_inode);
goto data_copy;
}
- if ((folio_has_private(folio[0]) &&
- !filemap_release_folio(folio[0], 0)) ||
- (folio_has_private(folio[1]) &&
- !filemap_release_folio(folio[1], 0))) {
+ if (!filemap_release_folio(folio[0], 0) ||
+ !filemap_release_folio(folio[1], 0)) {
*err = -EBUSY;
goto drop_data_sem;
}
@@ -362,10 +360,8 @@ data_copy:
/* At this point all buffers in range are uptodate, old mapping layout
* is no longer required, try to drop it now. */
- if ((folio_has_private(folio[0]) &&
- !filemap_release_folio(folio[0], 0)) ||
- (folio_has_private(folio[1]) &&
- !filemap_release_folio(folio[1], 0))) {
+ if (!filemap_release_folio(folio[0], 0) ||
+ !filemap_release_folio(folio[1], 0)) {
*err = -EBUSY;
goto unlock_folios;
}