diff options
| -rw-r--r-- | drivers/target/target_core_file.c | 41 | ||||
| -rw-r--r-- | drivers/target/target_core_file.h | 1 |
2 files changed, 39 insertions, 3 deletions
diff --git a/drivers/target/target_core_file.c b/drivers/target/target_core_file.c index 11119257e51..0360383dfb9 100644 --- a/drivers/target/target_core_file.c +++ b/drivers/target/target_core_file.c @@ -125,6 +125,19 @@ static struct se_device *fd_create_virtdevice( * of pure timestamp updates. */ flags = O_RDWR | O_CREAT | O_LARGEFILE | O_DSYNC; + /* + * Optionally allow fd_buffered_io=1 to be enabled for people + * who want use the fs buffer cache as an WriteCache mechanism. + * + * This means that in event of a hard failure, there is a risk + * of silent data-loss if the SCSI client has *not* performed a + * forced unit access (FUA) write, or issued SYNCHRONIZE_CACHE + * to write-out the entire device cache. + */ + if (fd_dev->fbd_flags & FDBD_HAS_BUFFERED_IO_WCE) { + pr_debug("FILEIO: Disabling O_DSYNC, using buffered FILEIO\n"); + flags &= ~O_DSYNC; + } file = filp_open(fd_dev->fd_dev_name, flags, 0600); if (IS_ERR(file)) { @@ -188,6 +201,12 @@ static struct se_device *fd_create_virtdevice( if (!dev) goto fail; + if (fd_dev->fbd_flags & FDBD_HAS_BUFFERED_IO_WCE) { + pr_debug("FILEIO: Forcing setting of emulate_write_cache=1" + " with FDBD_HAS_BUFFERED_IO_WCE\n"); + dev->se_sub_dev->se_dev_attrib.emulate_write_cache = 1; + } + fd_dev->fd_dev_id = fd_host->fd_host_dev_id_count++; fd_dev->fd_queue_depth = dev->queue_depth; @@ -407,6 +426,7 @@ enum { static match_table_t tokens = { {Opt_fd_dev_name, "fd_dev_name=%s"}, {Opt_fd_dev_size, "fd_dev_size=%s"}, + {Opt_fd_buffered_io, "fd_buffered_io=%d"}, {Opt_err, NULL} }; @@ -418,7 +438,7 @@ static ssize_t fd_set_configfs_dev_params( struct fd_dev *fd_dev = se_dev->se_dev_su_ptr; char *orig, *ptr, *arg_p, *opts; substring_t args[MAX_OPT_ARGS]; - int ret = 0, token; + int ret = 0, arg, token; opts = kstrdup(page, GFP_KERNEL); if (!opts) @@ -459,6 +479,19 @@ static ssize_t fd_set_configfs_dev_params( " bytes\n", fd_dev->fd_dev_size); fd_dev->fbd_flags |= FBDF_HAS_SIZE; break; + case Opt_fd_buffered_io: + match_int(args, &arg); + if (arg != 1) { + pr_err("bogus fd_buffered_io=%d value\n", arg); + ret = -EINVAL; + goto out; + } + + pr_debug("FILEIO: Using buffered I/O" + " operations for struct fd_dev\n"); + + fd_dev->fbd_flags |= FDBD_HAS_BUFFERED_IO_WCE; + break; default: break; } @@ -490,8 +523,10 @@ static ssize_t fd_show_configfs_dev_params( ssize_t bl = 0; bl = sprintf(b + bl, "TCM FILEIO ID: %u", fd_dev->fd_dev_id); - bl += sprintf(b + bl, " File: %s Size: %llu Mode: O_DSYNC\n", - fd_dev->fd_dev_name, fd_dev->fd_dev_size); + bl += sprintf(b + bl, " File: %s Size: %llu Mode: %s\n", + fd_dev->fd_dev_name, fd_dev->fd_dev_size, + (fd_dev->fbd_flags & FDBD_HAS_BUFFERED_IO_WCE) ? + "Buffered-WCE" : "O_DSYNC"); return bl; } diff --git a/drivers/target/target_core_file.h b/drivers/target/target_core_file.h index 70ce7fd7111..876ae53ef5b 100644 --- a/drivers/target/target_core_file.h +++ b/drivers/target/target_core_file.h @@ -14,6 +14,7 @@ #define FBDF_HAS_PATH 0x01 #define FBDF_HAS_SIZE 0x02 +#define FDBD_HAS_BUFFERED_IO_WCE 0x04 struct fd_dev { u32 fbd_flags; |