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authorPavel Shilovsky <piastry@etersoft.ru>2012-12-21 15:05:47 +0400
committerSteve French <smfrench@gmail.com>2013-01-01 22:59:55 -0600
commitca8aa29c60238720af2ca2a5caab25fa0c70067e (patch)
treecc5940d0c0acaa31b19793b456423764ac97afe0 /fs/cifs
parent31efee60f489c759c341454d755a9fd13de8c03d (diff)
Revert "CIFS: Fix write after setting a read lock for read oplock files"
that solution has data races and can end up two identical writes to the server: when clientCanCacheAll value can be changed during the execution of __generic_file_aio_write. Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru> Reviewed-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Steve French <smfrench@gmail.com>
Diffstat (limited to 'fs/cifs')
-rw-r--r--fs/cifs/cifsfs.c1
-rw-r--r--fs/cifs/cifsglob.h1
-rw-r--r--fs/cifs/file.c94
3 files changed, 31 insertions, 65 deletions
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index f653835d067..de7f9168a11 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -228,7 +228,6 @@ cifs_alloc_inode(struct super_block *sb)
cifs_set_oplock_level(cifs_inode, 0);
cifs_inode->delete_pending = false;
cifs_inode->invalid_mapping = false;
- cifs_inode->leave_pages_clean = false;
cifs_inode->vfs_inode.i_blkbits = 14; /* 2**14 = CIFS_MAX_MSGSIZE */
cifs_inode->server_eof = 0;
cifs_inode->uniqueid = 0;
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index aea1eec6491..dfab450a191 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -1030,7 +1030,6 @@ struct cifsInodeInfo {
bool clientCanCacheAll; /* read and writebehind oplock */
bool delete_pending; /* DELETE_ON_CLOSE is set */
bool invalid_mapping; /* pagecache is invalid */
- bool leave_pages_clean; /* protected by i_mutex, not set pages dirty */
unsigned long time; /* jiffies of last update of inode */
u64 server_eof; /* current file size on server -- protected by i_lock */
u64 uniqueid; /* server inode number */
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 0a6677ba212..1b322d041f1 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -2103,15 +2103,7 @@ static int cifs_write_end(struct file *file, struct address_space *mapping,
} else {
rc = copied;
pos += copied;
- /*
- * When we use strict cache mode and cifs_strict_writev was run
- * with level II oplock (indicated by leave_pages_clean field of
- * CIFS_I(inode)), we can leave pages clean - cifs_strict_writev
- * sent the data to the server itself.
- */
- if (!CIFS_I(inode)->leave_pages_clean ||
- !(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_STRICT_IO))
- set_page_dirty(page);
+ set_page_dirty(page);
}
if (rc > 0) {
@@ -2462,8 +2454,8 @@ ssize_t cifs_user_writev(struct kiocb *iocb, const struct iovec *iov,
}
static ssize_t
-cifs_pagecache_writev(struct kiocb *iocb, const struct iovec *iov,
- unsigned long nr_segs, loff_t pos, bool cache_ex)
+cifs_writev(struct kiocb *iocb, const struct iovec *iov,
+ unsigned long nr_segs, loff_t pos)
{
struct file *file = iocb->ki_filp;
struct cifsFileInfo *cfile = (struct cifsFileInfo *)file->private_data;
@@ -2485,12 +2477,8 @@ cifs_pagecache_writev(struct kiocb *iocb, const struct iovec *iov,
server->vals->exclusive_lock_type, NULL,
CIFS_WRITE_OP)) {
mutex_lock(&inode->i_mutex);
- if (!cache_ex)
- cinode->leave_pages_clean = true;
rc = __generic_file_aio_write(iocb, iov, nr_segs,
- &iocb->ki_pos);
- if (!cache_ex)
- cinode->leave_pages_clean = false;
+ &iocb->ki_pos);
mutex_unlock(&inode->i_mutex);
}
@@ -2517,62 +2505,42 @@ cifs_strict_writev(struct kiocb *iocb, const struct iovec *iov,
struct cifsFileInfo *cfile = (struct cifsFileInfo *)
iocb->ki_filp->private_data;
struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
- ssize_t written, written2;
+
+#ifdef CONFIG_CIFS_SMB2
/*
- * We need to store clientCanCacheAll here to prevent race
- * conditions - this value can be changed during an execution
- * of generic_file_aio_write. For CIFS it can be changed from
- * true to false only, but for SMB2 it can be changed both from
- * true to false and vice versa. So, we can end up with a data
- * stored in the cache, not marked dirty and not sent to the
- * server if this value changes its state from false to true
- * after cifs_write_end.
+ * If we have an oplock for read and want to write a data to the file
+ * we need to store it in the page cache and then push it to the server
+ * to be sure the next read will get a valid data.
*/
- bool cache_ex = cinode->clientCanCacheAll;
- bool cache_read = cinode->clientCanCacheRead;
- int rc;
- loff_t saved_pos;
+ if (!cinode->clientCanCacheAll && cinode->clientCanCacheRead) {
+ ssize_t written;
+ int rc;
+
+ written = generic_file_aio_write(iocb, iov, nr_segs, pos);
+ rc = filemap_fdatawrite(inode->i_mapping);
+ if (rc)
+ return (ssize_t)rc;
- if (cache_ex) {
- if (cap_unix(tcon->ses) &&
- ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOPOSIXBRL) == 0) &&
- (CIFS_UNIX_FCNTL_CAP & le64_to_cpu(
- tcon->fsUnixInfo.Capability)))
- return generic_file_aio_write(iocb, iov, nr_segs, pos);
- return cifs_pagecache_writev(iocb, iov, nr_segs, pos, cache_ex);
+ return written;
}
+#endif
/*
- * For files without exclusive oplock in strict cache mode we need to
- * write the data to the server exactly from the pos to pos+len-1 rather
- * than flush all affected pages because it may cause a error with
- * mandatory locks on these pages but not on the region from pos to
- * ppos+len-1.
+ * For non-oplocked files in strict cache mode we need to write the data
+ * to the server exactly from the pos to pos+len-1 rather than flush all
+ * affected pages because it may cause a error with mandatory locks on
+ * these pages but not on the region from pos to ppos+len-1.
*/
- written = cifs_user_writev(iocb, iov, nr_segs, pos);
- if (!cache_read || written <= 0)
- return written;
- saved_pos = iocb->ki_pos;
- iocb->ki_pos = pos;
- /* we have a read oplock - need to store a data in the page cache */
+ if (!cinode->clientCanCacheAll)
+ return cifs_user_writev(iocb, iov, nr_segs, pos);
+
if (cap_unix(tcon->ses) &&
- ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOPOSIXBRL) == 0) &&
- (CIFS_UNIX_FCNTL_CAP & le64_to_cpu(
- tcon->fsUnixInfo.Capability)))
- written2 = generic_file_aio_write(iocb, iov, nr_segs, pos);
- else
- written2 = cifs_pagecache_writev(iocb, iov, nr_segs, pos,
- cache_ex);
- /* errors occured during writing - invalidate the page cache */
- if (written2 < 0) {
- rc = cifs_invalidate_mapping(inode);
- if (rc)
- written = (ssize_t)rc;
- else
- iocb->ki_pos = saved_pos;
- }
- return written;
+ (CIFS_UNIX_FCNTL_CAP & le64_to_cpu(tcon->fsUnixInfo.Capability)) &&
+ ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOPOSIXBRL) == 0))
+ return generic_file_aio_write(iocb, iov, nr_segs, pos);
+
+ return cifs_writev(iocb, iov, nr_segs, pos);
}
static struct cifs_readdata *