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hw/9pfs: Add new virtfs option writeout=immediate skip host page cache

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writeout=immediate implies the after pwritev we do a sync_file_range.

Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
This commit is contained in:
Aneesh Kumar K.V 2011-10-12 19:11:23 +05:30
parent 5745e38afe
commit d3ab98e691
10 changed files with 91 additions and 17 deletions
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4
fsdev/file-op-9p.h
View File

@ -53,12 +53,16 @@ struct xattr_operations;
/* FsContext flag values */
#define PATHNAME_FSCONTEXT 0x1
/* export flags */
#define V9FS_IMMEDIATE_WRITEOUT 0x1
typedef struct FsContext
{
int flags;
char *fs_root;
SecModel fs_sm;
uid_t uid;
int export_flags;
struct xattr_operations **xops;
/* fs driver specific data */
void *private;

10
fsdev/qemu-fsdev.c
View File

@ -34,6 +34,8 @@ int qemu_fsdev_add(QemuOpts *opts)
const char *fstype = qemu_opt_get(opts, "fstype");
const char *path = qemu_opt_get(opts, "path");
const char *sec_model = qemu_opt_get(opts, "security_model");
const char *writeout = qemu_opt_get(opts, "writeout");
if (!fsdev_id) {
fprintf(stderr, "fsdev: No id specified\n");
@ -72,10 +74,14 @@ int qemu_fsdev_add(QemuOpts *opts)
fsle->fse.path = g_strdup(path);
fsle->fse.security_model = g_strdup(sec_model);
fsle->fse.ops = FsTypes[i].ops;
fsle->fse.export_flags = 0;
if (writeout) {
if (!strcmp(writeout, "immediate")) {
fsle->fse.export_flags = V9FS_IMMEDIATE_WRITEOUT;
}
}
QTAILQ_INSERT_TAIL(&fstype_entries, fsle, next);
return 0;
}
FsTypeEntry *get_fsdev_fsentry(char *id)

1
fsdev/qemu-fsdev.h
View File

@ -41,6 +41,7 @@ typedef struct FsTypeEntry {
char *fsdev_id;
char *path;
char *security_model;
int export_flags;
FileOperations *ops;
} FsTypeEntry;

1
hw/9pfs/virtio-9p-device.c
View File

@ -115,6 +115,7 @@ VirtIODevice *virtio_9p_init(DeviceState *dev, V9fsConf *conf)
exit(1);
}
s->ctx.export_flags = fse->export_flags;
s->ctx.fs_root = g_strdup(fse->path);
len = strlen(conf->tag);
if (len > MAX_TAG_LEN) {

17
hw/9pfs/virtio-9p-handle.c
View File

@ -192,16 +192,29 @@ static ssize_t handle_preadv(FsContext *ctx, int fd, const struct iovec *iov,
static ssize_t handle_pwritev(FsContext *ctx, int fd, const struct iovec *iov,
int iovcnt, off_t offset)
{
ssize_t ret;
#ifdef CONFIG_PREADV
return pwritev(fd, iov, iovcnt, offset);
ret = pwritev(fd, iov, iovcnt, offset);
#else
int err = lseek(fd, offset, SEEK_SET);
if (err == -1) {
return err;
} else {
return writev(fd, iov, iovcnt);
ret = writev(fd, iov, iovcnt);
}
#endif
#ifdef CONFIG_SYNC_FILE_RANGE
if (ret > 0 && ctx->export_flags & V9FS_IMMEDIATE_WRITEOUT) {
/*
* Initiate a writeback. This is not a data integrity sync.
* We want to ensure that we don't leave dirty pages in the cache
* after write when writeout=immediate is sepcified.
*/
sync_file_range(fd, offset, ret,
SYNC_FILE_RANGE_WAIT_BEFORE | SYNC_FILE_RANGE_WRITE);
}
#endif
return ret;
}
static int handle_chmod(FsContext *fs_ctx, V9fsPath *fs_path, FsCred *credp)

18
hw/9pfs/virtio-9p-local.c
View File

@ -203,16 +203,30 @@ static ssize_t local_preadv(FsContext *ctx, int fd, const struct iovec *iov,
static ssize_t local_pwritev(FsContext *ctx, int fd, const struct iovec *iov,
int iovcnt, off_t offset)
{
ssize_t ret
;
#ifdef CONFIG_PREADV
return pwritev(fd, iov, iovcnt, offset);
ret = pwritev(fd, iov, iovcnt, offset);
#else
int err = lseek(fd, offset, SEEK_SET);
if (err == -1) {
return err;
} else {
return writev(fd, iov, iovcnt);
ret = writev(fd, iov, iovcnt);
}
#endif
#ifdef CONFIG_SYNC_FILE_RANGE
if (ret > 0 && ctx->export_flags & V9FS_IMMEDIATE_WRITEOUT) {
/*
* Initiate a writeback. This is not a data integrity sync.
* We want to ensure that we don't leave dirty pages in the cache
* after write when writeout=immediate is sepcified.
*/
sync_file_range(fd, offset, ret,
SYNC_FILE_RANGE_WAIT_BEFORE | SYNC_FILE_RANGE_WRITE);
}
#endif
return ret;
}
static int local_chmod(FsContext *fs_ctx, V9fsPath *fs_path, FsCred *credp)

22
hw/9pfs/virtio-9p.c
View File

@ -80,6 +80,20 @@ void cred_init(FsCred *credp)
credp->fc_rdev = -1;
}
static int get_dotl_openflags(V9fsState *s, int oflags)
{
int flags;
/*
* Filter the client open flags
*/
flags = oflags & ~(O_NOCTTY | O_ASYNC | O_CREAT);
/*
* Ignore direct disk access hint until the server supports it.
*/
flags &= ~O_DIRECT;
return flags;
}
void v9fs_string_init(V9fsString *str)
{
str->data = NULL;
@ -1598,10 +1612,7 @@ static void v9fs_open(void *opaque)
err = offset;
} else {
if (s->proto_version == V9FS_PROTO_2000L) {
flags = mode;
flags &= ~(O_NOCTTY | O_ASYNC | O_CREAT);
/* Ignore direct disk access hint until the server supports it. */
flags &= ~O_DIRECT;
flags = get_dotl_openflags(s, mode);
} else {
flags = omode_to_uflags(mode);
}
@ -1650,8 +1661,7 @@ static void v9fs_lcreate(void *opaque)
goto out_nofid;
}
/* Ignore direct disk access hint until the server supports it. */
flags &= ~O_DIRECT;
flags = get_dotl_openflags(pdu->s, flags);
err = v9fs_co_open2(pdu, fidp, &name, gid,
flags | O_CREAT, mode, &stbuf);
if (err < 0) {

6
qemu-config.c
View File

@ -177,6 +177,9 @@ QemuOptsList qemu_fsdev_opts = {
}, {
.name = "security_model",
.type = QEMU_OPT_STRING,
}, {
.name = "writeout",
.type = QEMU_OPT_STRING,
},
{ /*End of list */ }
},
@ -199,6 +202,9 @@ QemuOptsList qemu_virtfs_opts = {
}, {
.name = "security_model",
.type = QEMU_OPT_STRING,
}, {
.name = "writeout",
.type = QEMU_OPT_STRING,
},
{ /*End of list */ }

17
qemu-options.hx
View File

@ -525,7 +525,8 @@ ETEXI
DEFHEADING(File system options:)
DEF("fsdev", HAS_ARG, QEMU_OPTION_fsdev,
"-fsdev local,id=id,path=path,security_model=[mapped|passthrough|none]\n",
"-fsdev local,id=id,path=path,security_model=[mapped|passthrough|none]\n"
" [,writeout=immediate]\n",
QEMU_ARCH_ALL)
STEXI
@ -541,7 +542,7 @@ The specific Fstype will determine the applicable options.
Options to each backend are described below.
@item -fsdev local ,id=@var{id} ,path=@var{path} ,security_model=@var{security_model}
@item -fsdev local ,id=@var{id} ,path=@var{path} ,security_model=@var{security_model}[,writeout=@var{writeout}]
Create a file-system-"device" for local-filesystem.
@ -552,13 +553,17 @@ Create a file-system-"device" for local-filesystem.
@option{security_model} specifies the security model to be followed.
@option{security_model} is required.
@option{writeout} specifies whether to skip the host page cache.
@option{writeout} is an optional argument.
@end table
ETEXI
DEFHEADING(Virtual File system pass-through options:)
DEF("virtfs", HAS_ARG, QEMU_OPTION_virtfs,
"-virtfs local,path=path,mount_tag=tag,security_model=[mapped|passthrough|none]\n",
"-virtfs local,path=path,mount_tag=tag,security_model=[mapped|passthrough|none]\n"
" [,writeout=immediate]\n",
QEMU_ARCH_ALL)
STEXI
@ -574,7 +579,7 @@ The specific Fstype will determine the applicable options.
Options to each backend are described below.
@item -virtfs local ,path=@var{path} ,mount_tag=@var{mount_tag} ,security_model=@var{security_model}
@item -virtfs local ,path=@var{path} ,mount_tag=@var{mount_tag} ,security_model=@var{security_model}[,writeout=@var{writeout}]
Create a Virtual file-system-pass through for local-filesystem.
@ -585,10 +590,12 @@ Create a Virtual file-system-pass through for local-filesystem.
@option{security_model} specifies the security model to be followed.
@option{security_model} is required.
@option{mount_tag} specifies the tag with which the exported file is mounted.
@option{mount_tag} is required.
@option{writeout} specifies whether to skip the host page cache.
@option{writeout} is an optional argument.
@end table
ETEXI

12
vl.c
View File

@ -2785,6 +2785,7 @@ int main(int argc, char **argv, char **envp)
case QEMU_OPTION_virtfs: {
QemuOpts *fsdev;
QemuOpts *device;
const char *writeout;
olist = qemu_find_opts("virtfs");
if (!olist) {
@ -2814,6 +2815,17 @@ int main(int argc, char **argv, char **envp)
qemu_opt_get(opts, "mount_tag"));
exit(1);
}
writeout = qemu_opt_get(opts, "writeout");
if (writeout) {
#ifdef CONFIG_SYNC_FILE_RANGE
qemu_opt_set(fsdev, "writeout", writeout);
#else
fprintf(stderr, "writeout=immediate not supported on "
"this platform\n");
exit(1);
#endif
}
qemu_opt_set(fsdev, "fstype", qemu_opt_get(opts, "fstype"));
qemu_opt_set(fsdev, "path", qemu_opt_get(opts, "path"));
qemu_opt_set(fsdev, "security_model",