Gitweb:
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=8a236264f7d6db3f52881d37a86c5a5f704072b0
Commit: 8a236264f7d6db3f52881d37a86c5a5f704072b0
Parent: c7af1857ef74873bf5a9c8fcab0cfd79883492ac
Author: Steve French <[EMAIL PROTECTED]>
AuthorDate: Tue Mar 6 00:31:00 2007 +0000
Committer: Steve French <[EMAIL PROTECTED]>
CommitDate: Tue Mar 6 00:31:00 2007 +0000
[CIFS] cifs_prepare_write was incorrectly rereading page in some cases
Noticed by Shaggy.
Signed-off-by: Shaggy <[EMAIL PROTECTED]>
Signed-off-by: Steve French <[EMAIL PROTECTED]>
---
fs/cifs/CHANGES | 5 ++-
fs/cifs/file.c | 62 ++++++++++++++++++++++++++++++++------------------
fs/cifs/transport.c | 6 +---
3 files changed, 45 insertions(+), 28 deletions(-)
diff --git a/fs/cifs/CHANGES b/fs/cifs/CHANGES
index e08a147..6247628 100644
--- a/fs/cifs/CHANGES
+++ b/fs/cifs/CHANGES
@@ -2,8 +2,9 @@ Verison 1.48
------------
Fix mtime bouncing around from local idea of last write times to remote time.
Fix hang (in i_size_read) when simultaneous size update of same remote file
-on smp system corrupts sequence number.
-
+on smp system corrupts sequence number. Do not reread unnecessarily partial
page
+(which we are about to overwrite anyway) when writing out file opened rw.
+
Version 1.47
------------
Fix oops in list_del during mount caused by unaligned string.
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index c07ff83..2d3275b 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -1992,34 +1992,52 @@ static int cifs_prepare_write(struct file *file, struct
page *page,
unsigned from, unsigned to)
{
int rc = 0;
- loff_t offset = (loff_t)page->index << PAGE_CACHE_SHIFT;
+ loff_t i_size;
+ loff_t offset;
+
cFYI(1, ("prepare write for page %p from %d to %d",page,from,to));
- if (!PageUptodate(page)) {
- /* if (to - from != PAGE_CACHE_SIZE) {
- void *kaddr = kmap_atomic(page, KM_USER0);
+ if (PageUptodate(page))
+ return 0;
+
+ /* If we are writing a full page it will be up to date,
+ no need to read from the server */
+ if ((to == PAGE_CACHE_SIZE) && (from == 0)) {
+ SetPageUptodate(page);
+ return 0;
+ }
+
+ offset = (loff_t)page->index << PAGE_CACHE_SHIFT;
+ i_size = i_size_read(page->mapping->host);
+
+ if ((offset >= i_size) ||
+ ((from == 0) && (offset + to) >= i_size)) {
+ /*
+ * We don't need to read data beyond the end of the file.
+ * zero it, and set the page uptodate
+ */
+ void *kaddr = kmap_atomic(page, KM_USER0);
+
+ if (from)
memset(kaddr, 0, from);
+ if (to < PAGE_CACHE_SIZE)
memset(kaddr + to, 0, PAGE_CACHE_SIZE - to);
- flush_dcache_page(page);
- kunmap_atomic(kaddr, KM_USER0);
- } */
- /* If we are writing a full page it will be up to date,
- no need to read from the server */
- if ((to == PAGE_CACHE_SIZE) && (from == 0))
- SetPageUptodate(page);
-
+ flush_dcache_page(page);
+ kunmap_atomic(kaddr, KM_USER0);
+ SetPageUptodate(page);
+ } else if ((file->f_flags & O_ACCMODE) != O_WRONLY) {
/* might as well read a page, it is fast enough */
- if ((file->f_flags & O_ACCMODE) != O_WRONLY) {
- rc = cifs_readpage_worker(file, page, &offset);
- } else {
- /* should we try using another file handle if there is one -
- how would we lock it to prevent close of that handle
- racing with this read?
- In any case this will be written out by commit_write */
- }
+ rc = cifs_readpage_worker(file, page, &offset);
+ } 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 commit_write so is fine */
}
- /* BB should we pass any errors back?
- e.g. if we do not have read access to the file */
+ /* we do not need to pass errors back
+ e.g. if we do not have read access to the file
+ because cifs_commit_write will do the right thing. -- shaggy */
+
return 0;
}
diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
index f80007e..5f46845 100644
--- a/fs/cifs/transport.c
+++ b/fs/cifs/transport.c
@@ -499,7 +499,7 @@ SendReceive2(const unsigned int xid, struct cifsSesInfo
*ses,
due to last connection to this server being unmounted */
if (signal_pending(current)) {
/* if signal pending do not hold up user for full smb timeout
- but we still give response a change to complete */
+ but we still give response a chance to complete */
timeout = 2 * HZ;
}
@@ -587,7 +587,6 @@ SendReceive2(const unsigned int xid, struct cifsSesInfo
*ses,
}
out:
-
DeleteMidQEntry(midQ);
atomic_dec(&ses->server->inFlight);
wake_up(&ses->server->request_q);
@@ -681,7 +680,7 @@ SendReceive(const unsigned int xid, struct cifsSesInfo *ses,
due to last connection to this server being unmounted */
if (signal_pending(current)) {
/* if signal pending do not hold up user for full smb timeout
- but we still give response a change to complete */
+ but we still give response a chance to complete */
timeout = 2 * HZ;
}
@@ -765,7 +764,6 @@ SendReceive(const unsigned int xid, struct cifsSesInfo *ses,
}
out:
-
DeleteMidQEntry(midQ);
atomic_dec(&ses->server->inFlight);
wake_up(&ses->server->request_q);
-
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