diff options
| -rw-r--r-- | fs/cifs/CHANGES | 4 | ||||
| -rw-r--r-- | fs/cifs/README | 22 | ||||
| -rw-r--r-- | fs/cifs/cifs_fs_sb.h | 1 | ||||
| -rw-r--r-- | fs/cifs/connect.c | 7 | ||||
| -rw-r--r-- | fs/cifs/file.c | 3 |
5 files changed, 31 insertions, 6 deletions
diff --git a/fs/cifs/CHANGES b/fs/cifs/CHANGES index d43e0fe3339..b33c8412e2c 100644 --- a/fs/cifs/CHANGES +++ b/fs/cifs/CHANGES @@ -8,7 +8,9 @@ user's smb session. This fix allows cifs to mount multiple times to the same server with different userids without risking invalidating earlier established security contexts. fsync now sends SMB Flush operation to better ensure that we wait for server to write all of the data to -server disk (not just write it over the network). +server disk (not just write it over the network). Add new mount +parameter to allow user to disable sending the (slow) SMB flush on +fsync if desired (fsync still flushes all cached write data to the server). Version 1.56 ------------ diff --git a/fs/cifs/README b/fs/cifs/README index da4515e3be2..07434181623 100644 --- a/fs/cifs/README +++ b/fs/cifs/README @@ -472,6 +472,19 @@ A partial list of the supported mount options follows: even if the cifs server would support posix advisory locks. "forcemand" is accepted as a shorter form of this mount option. + nostrictsync If this mount option is set, when an application does an + fsync call then the cifs client does not send an SMB Flush + to the server (to force the server to write all dirty data + for this file immediately to disk), although cifs still sends + all dirty (cached) file data to the server and waits for the + server to respond to the write. Since SMB Flush can be + very slow, and some servers may be reliable enough (to risk + delaying slightly flushing the data to disk on the server), + turning on this option may be useful to improve performance for + applications that fsync too much, at a small risk of server + crash. If this mount option is not set, by default cifs will + send an SMB flush request (and wait for a response) on every + fsync call. nodfs Disable DFS (global name space support) even if the server claims to support it. This can help work around a problem with parsing of DFS paths with Samba server @@ -692,13 +705,14 @@ require this helper. Note that NTLMv2 security (which does not require the cifs.upcall helper program), instead of using Kerberos, is sufficient for some use cases. -Enabling DFS support (used to access shares transparently in an MS-DFS -global name space) requires that CONFIG_CIFS_EXPERIMENTAL be enabled. In -addition, DFS support for target shares which are specified as UNC +DFS support allows transparent redirection to shares in an MS-DFS name space. +In addition, DFS support for target shares which are specified as UNC names which begin with host names (rather than IP addresses) requires a user space helper (such as cifs.upcall) to be present in order to translate host names to ip address, and the user space helper must also -be configured in the file /etc/request-key.conf +be configured in the file /etc/request-key.conf. Samba, Windows servers and +many NAS appliances support DFS as a way of constructing a global name +space to ease network configuration and improve reliability. To use cifs Kerberos and DFS support, the Linux keyutils package should be installed and something like the following lines should be added to the diff --git a/fs/cifs/cifs_fs_sb.h b/fs/cifs/cifs_fs_sb.h index c4c306f7b06..e9f177bb065 100644 --- a/fs/cifs/cifs_fs_sb.h +++ b/fs/cifs/cifs_fs_sb.h @@ -32,6 +32,7 @@ #define CIFS_MOUNT_OVERR_GID 0x800 /* override gid returned from server */ #define CIFS_MOUNT_DYNPERM 0x1000 /* allow in-memory only mode setting */ #define CIFS_MOUNT_NOPOSIXBRL 0x2000 /* mandatory not posix byte range lock */ +#define CIFS_MOUNT_NO_SSYNC 0x4000 /* don't do slow SMBflush on every sync*/ struct cifs_sb_info { struct cifsTconInfo *tcon; /* primary mount */ diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c index da0f4ffa061..18e84a4e050 100644 --- a/fs/cifs/connect.c +++ b/fs/cifs/connect.c @@ -95,6 +95,7 @@ struct smb_vol { bool local_lease:1; /* check leases only on local system, not remote */ bool noblocksnd:1; bool noautotune:1; + bool nostrictsync:1; /* do not force expensive SMBflush on every sync */ unsigned int rsize; unsigned int wsize; unsigned int sockopt; @@ -1274,6 +1275,10 @@ cifs_parse_mount_options(char *options, const char *devname, vol->intr = 0; } else if (strnicmp(data, "intr", 4) == 0) { vol->intr = 1; + } else if (strnicmp(data, "nostrictsync", 12) == 0) { + vol->nostrictsync = 1; + } else if (strnicmp(data, "strictsync", 10) == 0) { + vol->nostrictsync = 0; } else if (strnicmp(data, "serverino", 7) == 0) { vol->server_ino = 1; } else if (strnicmp(data, "noserverino", 9) == 0) { @@ -2160,6 +2165,8 @@ static void setup_cifs_sb(struct smb_vol *pvolume_info, cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_UNX_EMUL; if (pvolume_info->nobrl) cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_NO_BRL; + if (pvolume_info->nostrictsync) + cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_NO_SSYNC; if (pvolume_info->mand_lock) cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_NOPOSIXBRL; if (pvolume_info->cifs_acl) diff --git a/fs/cifs/file.c b/fs/cifs/file.c index 83b4741b6ad..6411f5f65d7 100644 --- a/fs/cifs/file.c +++ b/fs/cifs/file.c @@ -1538,7 +1538,8 @@ int cifs_fsync(struct file *file, struct dentry *dentry, int datasync) rc = CIFS_I(inode)->write_behind_rc; CIFS_I(inode)->write_behind_rc = 0; tcon = CIFS_SB(inode->i_sb)->tcon; - if (!rc && tcon && smbfile) + if (!rc && tcon && smbfile && + !(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_SSYNC)) rc = CIFSSMBFlush(xid, tcon, smbfile->netfid); } |