From: David Howells dhowells@redhat.com
[ Upstream commit fa04a40b169fcee615afbae97f71a09332993f64 ]
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 Signed-off-by: Sasha Levin sashal@kernel.org --- fs/afs/dir.c | 12 ++++-------- fs/afs/dir_edit.c | 6 ++---- fs/afs/file.c | 8 ++------ fs/afs/write.c | 18 ++++++++++-------- 4 files changed, 18 insertions(+), 26 deletions(-)
diff --git a/fs/afs/dir.c b/fs/afs/dir.c index 1d2e61e0ab047..1bb5b9d7f0a2c 100644 --- a/fs/afs/dir.c +++ b/fs/afs/dir.c @@ -281,8 +281,7 @@ retry: if (ret < 0) goto error;
- set_page_private(req->pages[i], 1); - SetPagePrivate(req->pages[i]); + attach_page_private(req->pages[i], (void *)1); unlock_page(req->pages[i]); i++; } else { @@ -1975,8 +1974,7 @@ static int afs_dir_releasepage(struct page *page, gfp_t gfp_flags)
_enter("{{%llx:%llu}[%lu]}", dvnode->fid.vid, dvnode->fid.vnode, page->index);
- set_page_private(page, 0); - ClearPagePrivate(page); + detach_page_private(page);
/* The directory will need reloading. */ if (test_and_clear_bit(AFS_VNODE_DIR_VALID, &dvnode->flags)) @@ -2003,8 +2001,6 @@ static void afs_dir_invalidatepage(struct page *page, unsigned int offset, afs_stat_v(dvnode, n_inval);
/* we clean up only if the entire page is being invalidated */ - if (offset == 0 && length == PAGE_SIZE) { - set_page_private(page, 0); - ClearPagePrivate(page); - } + if (offset == 0 && length == PAGE_SIZE) + detach_page_private(page); } diff --git a/fs/afs/dir_edit.c b/fs/afs/dir_edit.c index b108528bf010d..2ffe09abae7fc 100644 --- a/fs/afs/dir_edit.c +++ b/fs/afs/dir_edit.c @@ -243,10 +243,8 @@ void afs_edit_dir_add(struct afs_vnode *vnode, index, gfp); if (!page) goto error; - if (!PagePrivate(page)) { - set_page_private(page, 1); - SetPagePrivate(page); - } + if (!PagePrivate(page)) + attach_page_private(page, (void *)1); dir_page = kmap(page); }
diff --git a/fs/afs/file.c b/fs/afs/file.c index 371d1488cc549..bdcf418e4a5c0 100644 --- a/fs/afs/file.c +++ b/fs/afs/file.c @@ -626,11 +626,9 @@ static void afs_invalidatepage(struct page *page, unsigned int offset, #endif
if (PagePrivate(page)) { - priv = page_private(page); + priv = (unsigned long)detach_page_private(page); trace_afs_page_dirty(vnode, tracepoint_string("inval"), page->index, priv); - set_page_private(page, 0); - ClearPagePrivate(page); } }
@@ -660,11 +658,9 @@ static int afs_releasepage(struct page *page, gfp_t gfp_flags) #endif
if (PagePrivate(page)) { - priv = page_private(page); + priv = (unsigned long)detach_page_private(page); trace_afs_page_dirty(vnode, tracepoint_string("rel"), page->index, priv); - set_page_private(page, 0); - ClearPagePrivate(page); }
/* indicate that the page can be released */ diff --git a/fs/afs/write.c b/fs/afs/write.c index b937ec047ec98..02facb19a0f1d 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)) {