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| author | David Howells <dhowells@redhat.com> | 2020-10-21 13:22:19 +0100 |
|---|---|---|
| committer | David Howells <dhowells@redhat.com> | 2020-10-29 13:53:04 +0000 |
| commit | fa04a40b169fcee615afbae97f71a09332993f64 (patch) | |
| tree | 3a6123e3b15b9881cd1227f5c129d5e3f8c36732 /fs/afs/write.c | |
| parent | d383e346f97d6bb0d654bb3d63c44ab106d92d29 (diff) | |
| download | linux-fa04a40b169fcee615afbae97f71a09332993f64.tar.bz2 | |
afs: Fix to take ref on page when PG_private is set
Fix afs to take a ref on a page when it sets PG_private on it and to drop
the ref when removing the flag.
Note that in afs_write_begin(), a lot of the time, PG_private is already
set on a page to which we're going to add some data. In such a case, we
leave the bit set and mustn't increment the page count.
As suggested by Matthew Wilcox, use attach/detach_page_private() where
possible.
Fixes: 31143d5d515e ("AFS: implement basic file write support")
Reported-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Diffstat (limited to 'fs/afs/write.c')
| -rw-r--r-- | fs/afs/write.c | 18 |
1 files changed, 10 insertions, 8 deletions
diff --git a/fs/afs/write.c b/fs/afs/write.c index b937ec047ec9..02facb19a0f1 100644 --- a/fs/afs/write.c +++ b/fs/afs/write.c @@ -151,8 +151,10 @@ try_again: priv |= f; trace_afs_page_dirty(vnode, tracepoint_string("begin"), page->index, priv); - SetPagePrivate(page); - set_page_private(page, priv); + if (PagePrivate(page)) + set_page_private(page, priv); + else + attach_page_private(page, (void *)priv); _leave(" = 0"); return 0; @@ -334,10 +336,9 @@ static void afs_pages_written_back(struct afs_vnode *vnode, ASSERTCMP(pv.nr, ==, count); for (loop = 0; loop < count; loop++) { - priv = page_private(pv.pages[loop]); + priv = (unsigned long)detach_page_private(pv.pages[loop]); trace_afs_page_dirty(vnode, tracepoint_string("clear"), pv.pages[loop]->index, priv); - set_page_private(pv.pages[loop], 0); end_page_writeback(pv.pages[loop]); } first += count; @@ -863,8 +864,10 @@ vm_fault_t afs_page_mkwrite(struct vm_fault *vmf) priv |= 0; /* From */ trace_afs_page_dirty(vnode, tracepoint_string("mkwrite"), vmf->page->index, priv); - SetPagePrivate(vmf->page); - set_page_private(vmf->page, priv); + if (PagePrivate(vmf->page)) + set_page_private(vmf->page, priv); + else + attach_page_private(vmf->page, (void *)priv); file_update_time(file); sb_end_pagefault(inode->i_sb); @@ -926,10 +929,9 @@ int afs_launder_page(struct page *page) ret = afs_store_data(mapping, page->index, page->index, t, f, true); } + priv = (unsigned long)detach_page_private(page); trace_afs_page_dirty(vnode, tracepoint_string("laundered"), page->index, priv); - set_page_private(page, 0); - ClearPagePrivate(page); #ifdef CONFIG_AFS_FSCACHE if (PageFsCache(page)) { |