@@ -43,6 +43,7 @@ typedef struct NFSClient {
int events;
bool has_zero_init;
AioContext *aio_context;
+ blkcnt_t st_blocks;
} NFSClient;
typedef struct NFSRPC {
@@ -374,6 +375,7 @@ static int64_t nfs_client_open(NFSClient *client, const char *filename,
}
ret = DIV_ROUND_UP(st.st_size, BDRV_SECTOR_SIZE);
+ client->st_blocks = st.st_blocks;
client->has_zero_init = S_ISREG(st.st_mode);
goto out;
fail:
@@ -464,6 +466,11 @@ static int64_t nfs_get_allocated_file_size(BlockDriverState *bs)
NFSRPC task = {0};
struct stat st;
+ if (bdrv_is_read_only(bs) &&
+ !(bs->open_flags & BDRV_O_NOCACHE)) {
+ return client->st_blocks * 512;
+ }
+
task.st = &st;
if (nfs_fstat_async(client->context, client->fh, nfs_co_generic_cb,
&task) != 0) {
@@ -484,6 +491,34 @@ static int nfs_file_truncate(BlockDriverState *bs, int64_t offset)
return nfs_ftruncate(client->context, client->fh, offset);
}
+/* Note that this will not re-establish a connection with the NFS server
+ * - it is effectively a NOP. */
+static int nfs_reopen_prepare(BDRVReopenState *state,
+ BlockReopenQueue *queue, Error **errp)
+{
+ NFSClient *client = state->bs->opaque;
+ struct stat st;
+ int ret = 0;
+
+ if (state->flags & BDRV_O_RDWR && bdrv_is_read_only(state->bs)) {
+ error_setg(errp, "Cannot open a read-only mount as read-write");
+ return -EACCES;
+ }
+
+ /* Update cache for read-only reopens */
+ if (!(state->flags & BDRV_O_RDWR)) {
+ ret = nfs_fstat(client->context, client->fh, &st);
+ if (ret < 0) {
+ error_setg(errp, "Failed to fstat file: %s",
+ nfs_get_error(client->context));
+ return ret;
+ }
+ client->st_blocks = st.st_blocks;
+ }
+
+ return 0;
+}
+
static BlockDriver bdrv_nfs = {
.format_name = "nfs",
.protocol_name = "nfs",
@@ -499,6 +534,7 @@ static BlockDriver bdrv_nfs = {
.bdrv_file_open = nfs_file_open,
.bdrv_close = nfs_file_close,
.bdrv_create = nfs_file_create,
+ .bdrv_reopen_prepare = nfs_reopen_prepare,
.bdrv_co_readv = nfs_co_readv,
.bdrv_co_writev = nfs_co_writev,
If the file is readonly its not expected to grow so save the blocking call to nfs_fstat_async and use the value saved at connection time. Also important the monitor (and thus the main loop) will not hang if block device info is queried and the NFS share is unresponsive. Signed-off-by: Peter Lieven <pl@kamp.de> --- v1->v2: update cache on reopen_prepare [Max] v2->v3: use cache only if cache.direct=off [Max] block/nfs.c | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+)