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authorLinus Torvalds <torvalds@linux-foundation.org>2008-11-30 14:04:02 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2008-11-30 14:04:02 -0800
commit8e36a5d6ad587d906f0ff677974e5edb0335db30 (patch)
treeff005c92b621a0f7da159bfaf45bc0fcc4af4b28 /fs
parent9bd062d9eaf9e790330f37d9f4518e1b95131f6c (diff)
parenta98ee8c1c707fe3210b00ef9f806ba8e2bf35504 (diff)
downloadconfigs-8e36a5d6ad587d906f0ff677974e5edb0335db30.tar.gz
Merge git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6
* git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6: [CIFS] fix regression in cifs_write_begin/cifs_write_end
Diffstat (limited to 'fs')
-rw-r--r--fs/cifs/file.c77
1 files changed, 56 insertions, 21 deletions
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index b691b893a84..f0a81e631ae 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -1475,7 +1475,11 @@ static int cifs_write_end(struct file *file, struct address_space *mapping,
cFYI(1, ("write_end for page %p from pos %lld with %d bytes",
page, pos, copied));
- if (!PageUptodate(page) && copied == PAGE_CACHE_SIZE)
+ if (PageChecked(page)) {
+ if (copied == len)
+ SetPageUptodate(page);
+ ClearPageChecked(page);
+ } else if (!PageUptodate(page) && copied == PAGE_CACHE_SIZE)
SetPageUptodate(page);
if (!PageUptodate(page)) {
@@ -2062,39 +2066,70 @@ static int cifs_write_begin(struct file *file, struct address_space *mapping,
{
pgoff_t index = pos >> PAGE_CACHE_SHIFT;
loff_t offset = pos & (PAGE_CACHE_SIZE - 1);
+ loff_t page_start = pos & PAGE_MASK;
+ loff_t i_size;
+ struct page *page;
+ int rc = 0;
cFYI(1, ("write_begin from %lld len %d", (long long)pos, len));
- *pagep = __grab_cache_page(mapping, index);
- if (!*pagep)
- return -ENOMEM;
-
- if (PageUptodate(*pagep))
- return 0;
+ page = __grab_cache_page(mapping, index);
+ if (!page) {
+ rc = -ENOMEM;
+ goto out;
+ }
- /* If we are writing a full page it will be up to date,
- no need to read from the server */
- if (len == PAGE_CACHE_SIZE && flags & AOP_FLAG_UNINTERRUPTIBLE)
- return 0;
+ if (PageUptodate(page))
+ goto out;
- if ((file->f_flags & O_ACCMODE) != O_WRONLY) {
- int rc;
+ /*
+ * If we write a full page it will be up to date, no need to read from
+ * the server. If the write is short, we'll end up doing a sync write
+ * instead.
+ */
+ if (len == PAGE_CACHE_SIZE)
+ goto out;
- /* might as well read a page, it is fast enough */
- rc = cifs_readpage_worker(file, *pagep, &offset);
+ /*
+ * optimize away the read when we have an oplock, and we're not
+ * expecting to use any of the data we'd be reading in. That
+ * is, when the page lies beyond the EOF, or straddles the EOF
+ * and the write will cover all of the existing data.
+ */
+ if (CIFS_I(mapping->host)->clientCanCacheRead) {
+ i_size = i_size_read(mapping->host);
+ if (page_start >= i_size ||
+ (offset == 0 && (pos + len) >= i_size)) {
+ zero_user_segments(page, 0, offset,
+ offset + len,
+ PAGE_CACHE_SIZE);
+ /*
+ * PageChecked means that the parts of the page
+ * to which we're not writing are considered up
+ * to date. Once the data is copied to the
+ * page, it can be set uptodate.
+ */
+ SetPageChecked(page);
+ goto out;
+ }
+ }
- /* we do not need to pass errors back
- e.g. if we do not have read access to the file
- because cifs_write_end will attempt synchronous writes
- -- shaggy */
+ if ((file->f_flags & O_ACCMODE) != O_WRONLY) {
+ /*
+ * might as well read a page, it is fast enough. If we get
+ * an error, we don't need to return it. cifs_write_end will
+ * do a sync write instead since PG_uptodate isn't set.
+ */
+ cifs_readpage_worker(file, page, &page_start);
} else {
/* we could try using another file handle if there is one -
but how would we lock it to prevent close of that handle
racing with this read? In any case
this will be written out by write_end so is fine */
}
-
- return 0;
+out:
+ *pagep = page;
+ return rc;
}
const struct address_space_operations cifs_addr_ops = {