search for: file_pwrit

...32_t count, uint64_t offset) +file_pread (void *handle, void *buf, uint32_t count, uint64_t offset, + uint32_t flags) { struct handle *h = handle; @@ -289,7 +312,8 @@ file_pread (void *handle, void *buf, uint32_t count, uint64_t offset) /* Write data to the file. */ static int -file_pwrite (void *handle, const void *buf, uint32_t count, uint64_t offset) +file_pwrite (void *handle, const void *buf, uint32_t count, uint64_t offset, + uint32_t flags) { struct handle *h = handle; @@ -304,6 +328,9 @@ file_pwrite (void *handle, const void *buf, uint32_t count, uint64_t o...

...t we prefer to advertise it only when we can + * actually (attempt to) punch holes. */ +#ifdef FALLOC_FL_PUNCH_HOLE + return 1; +#else + return 0; +#endif +} + /* Read data from the file. */ static int file_pread (void *handle, void *buf, uint32_t count, uint64_t offset) @@ -219,7 +231,7 @@ file_pwrite (void *handle, const void *buf, uint32_t count, uint64_t offset) return 0; } -/* Write data to the file. */ +/* Write zeroes to the file. */ static int file_zero (void *handle, uint32_t count, uint64_t offset, int may_trim) { @@ -268,6 +280,33 @@ file_flush (void *handle) return 0; }...

...t offset, #ifdef HAVE_POSIX_FADVISE /* On Linux this will evict the pages we just read from the page cache. */ - if (cache_mode == cache_none) + if (cache_mode == cache_writethrough) posix_fadvise (h->fd, orig_offset, orig_count, POSIX_FADV_DONTNEED); #endif @@ -441,11 +441,11 @@ file_pwrite (void *handle, const void *buf, uint32_t count, uint64_t offset, uint32_t orig_count = count; uint64_t orig_offset = offset; - /* If cache=none we want to force pages we have just written to the - * file to be flushed to disk so we can immediately evict them from - * the page cache. +...

..._t offset, offset += r; } +#ifdef HAVE_POSIX_FADVISE + /* On Linux this will evict the pages we just read from the page cache. */ + if (cache_mode == cache_none) + posix_fadvise (h->fd, orig_offset, orig_count, POSIX_FADV_DONTNEED); +#endif + return 0; } @@ -355,6 +428,17 @@ file_pwrite (void *handle, const void *buf, uint32_t count, uint64_t offset, { struct handle *h = handle; +#if defined (HAVE_POSIX_FADVISE) && defined (POSIX_FADV_DONTNEED) + uint32_t orig_count = count; + uint64_t orig_offset = offset; + + /* If cache=none we want to force pages we have just...

...O_DIRECT implementation, but my idea was that it might be an alternate implementation of cache=none. But if we thought we might use O_DIRECT as a separate mode, then maybe we should rename cache=none. cache=advise? cache=dontneed? I can't think of a good name! > >@@ -355,6 +428,17 @@ file_pwrite (void *handle, const void *buf, uint32_t count, uint64_t offset, > > { > > struct handle *h = handle; > >+#if defined (HAVE_POSIX_FADVISE) && defined (POSIX_FADV_DONTNEED) > >+ uint32_t orig_count = count; > >+ uint64_t orig_offset = offset; > >+ &...

...ISE > /* On Linux this will evict the pages we just read from the page cache. */ > - if (cache_mode == cache_none) > + if (cache_mode == cache_writethrough) > posix_fadvise (h->fd, orig_offset, orig_count, POSIX_FADV_DONTNEED); > #endif > > @@ -441,11 +441,11 @@ file_pwrite (void *handle, const void *buf, uint32_t count, uint64_t offset, > uint32_t orig_count = count; > uint64_t orig_offset = offset; > > - /* If cache=none we want to force pages we have just written to the > - * file to be flushed to disk so we can immediately evict them fro...

...also possible to avoid polluting the page cache by using O_DIRECT, but that comes with harder guarantees (aligned access through aligned buffers), so we may add it as another mode later on. But in the meantime, cache=none is fairly nice while still avoiding O_DIRECT. > @@ -355,6 +428,17 @@ file_pwrite (void *handle, const void *buf, uint32_t count, uint64_t offset, > { > struct handle *h = handle; > > +#if defined (HAVE_POSIX_FADVISE) && defined (POSIX_FADV_DONTNEED) > + uint32_t orig_count = count; > + uint64_t orig_offset = offset; > + > + /* If cac...

...CT > as a separate mode, then maybe we should rename cache=none. > cache=advise? cache=dontneed? I can't think of a good name! > Yes, don't call it none if you use the cache. How about advise=? I would keep cache semantics similar to qemu. > > >@@ -355,6 +428,17 @@ file_pwrite (void *handle, const void *buf, > uint32_t count, uint64_t offset, > > > { > > > struct handle *h = handle; > > >+#if defined (HAVE_POSIX_FADVISE) && defined (POSIX_FADV_DONTNEED) > > >+ uint32_t orig_count = count; > > >+ uint64_t orig...

...will evict the pages we just read from the page cache. */ > > - if (cache_mode == cache_none) > > + if (cache_mode == cache_writethrough) > > posix_fadvise (h->fd, orig_offset, orig_count, POSIX_FADV_DONTNEED); > > #endif > > > > @@ -441,11 +441,11 @@ file_pwrite (void *handle, const void *buf, uint32_t count, uint64_t offset, > > uint32_t orig_count = count; > > uint64_t orig_offset = offset; > > > > - /* If cache=none we want to force pages we have just written to the > > - * file to be flushed to disk so we can imm...

First thing to say is that I need to do a *lot* more testing on this, so this is just an early peek. In particular, although it passed ‘make check && make check-valgrind’ I have *not* tested it against a multi-conn-aware client such as the Linux kernel >= 4.9. This implements NBD_FLAG_CAN_MULTI_CONN, described in the protocol doc as: "NBD_FLAG_CAN_MULTI_CONN: Indicates that

...nt readonly) return NULL; } +#ifdef FALLOC_FL_PUNCH_HOLE + h->can_punch_hole = true; +#else + h->can_punch_hole = false; +#endif + +#ifdef FALLOC_FL_ZERO_RANGE + h->can_zero_range = true; +#else + h->can_zero_range = false; +#endif + return h; } @@ -252,34 +267,42 @@ file_pwrite (void *handle, const void *buf, uint32_t count, uint64_t offset) static int file_zero (void *handle, uint32_t count, uint64_t offset, int may_trim) { -#if defined(FALLOC_FL_PUNCH_HOLE) || defined(FALLOC_FL_ZERO_RANGE) struct handle *h = handle; -#endif int r = -1; #ifdef FALLOC_FL_PUNC...

...nt readonly) return NULL; } +#ifdef FALLOC_FL_PUNCH_HOLE + h->can_punch_hole = true; +#else + h->can_punch_hole = false; +#endif + +#ifdef FALLOC_FL_ZERO_RANGE + h->can_zero_range = true; +#else + h->can_zero_range = false; +#endif + return h; } @@ -252,34 +267,42 @@ file_pwrite (void *handle, const void *buf, uint32_t count, uint64_t offset) static int file_zero (void *handle, uint32_t count, uint64_t offset, int may_trim) { -#if defined(FALLOC_FL_PUNCH_HOLE) || defined(FALLOC_FL_ZERO_RANGE) struct handle *h = handle; -#endif int r = -1; #ifdef FALLOC_FL_PUNC...

...nt readonly) return NULL; } +#ifdef FALLOC_FL_PUNCH_HOLE + h->can_punch_hole = true; +#else + h->can_punch_hole = false; +#endif + +#ifdef FALLOC_FL_ZERO_RANGE + h->can_zero_range = true; +#else + h->can_zero_range = false; +#endif + return h; } @@ -252,35 +267,43 @@ file_pwrite (void *handle, const void *buf, uint32_t count, uint64_t offset) static int file_zero (void *handle, uint32_t count, uint64_t offset, int may_trim) { -#if defined(FALLOC_FL_PUNCH_HOLE) || defined(FALLOC_FL_ZERO_RANGE) struct handle *h = handle; -#endif - int r = -1; + int r; #ifdef FALL...

For existing commits, this is almost identical to v1, except that I updated some commit messages and reordered the commits in a somewhat more logical sequence. The main changes are the extra commits: [06/11] plugins: Return NBD_FLAG_CAN_MULTI_CONN from some readonly plugins. - Readonly plugins that can set the flag unconditionally. [09/11] partitioning: Return NBD_FLAG_CAN_MULTI_CONN. [10/11]

The upstream protocol recently promoted NBD_CMD_WRITE_ZEROES from experimental to a documented extension. Exposing support for this allows plugin writers to create sparse files when driven by a client that knows how to use the extension; meanwhile, even if a plugin does not support this extension, the server benefits from less network traffic from the client. Eric Blake (5): protocol: Support

...fpathconf() to definitively learn what will work on a given - * fd for a more precise answer; oh well. */ -#ifdef FALLOC_FL_PUNCH_HOLE - return 1; -#else - return 0; -#endif + struct handle *h = handle; + return h->can_punch_hole; } /* Read data from the file. */ @@ -252,34 +263,42 @@ file_pwrite (void *handle, const void *buf, uint32_t count, uint64_t offset) static int file_zero (void *handle, uint32_t count, uint64_t offset, int may_trim) { -#if defined(FALLOC_FL_PUNCH_HOLE) || defined(FALLOC_FL_ZERO_RANGE) struct handle *h = handle; -#endif int r = -1; #ifdef FALLOC_FL_PUNC...

.../* Regular file. */ + struct stat statbuf; + + if (fstat (h->fd, &statbuf) == -1) { + nbdkit_error ("fstat: %m"); + return -1; + } - /* Else regular file. */ - return statbuf.st_size; + return statbuf.st_size; + } } static int @@ -250,33 +277,86 @@ file_pwrite (void *handle, const void *buf, uint32_t count, uint64_t offset) static int file_zero (void *handle, uint32_t count, uint64_t offset, int may_trim) { -#if defined(FALLOC_FL_PUNCH_HOLE) || defined(FALLOC_FL_ZERO_RANGE) struct handle *h = handle; -#endif int r = -1; #ifdef FALLOC_FL_PUNC...

This is the second version to support efficient zero for block devices on older kernels (e.g. RHEL 7.5), and file systems that do not support yet FALLOC_FS_ZERO_RANGE (e.g. NFS 4.2). Changes since v1: - Split to smaller patches - Skip linux only includes on other systems - Skip code using BLKZEROOUT if the macro is not defined - Try BLKZEROOUT only if the offset and count are aligned to device

...{ - nbdkit_error ("pread: %m"); - return -1; - } - if (r == 0) { - nbdkit_error ("pread: unexpected end of file"); - return -1; - } - buf += r; - count -= r; - offset += r; - } - - return 0; -} - -/* Write data to the file. */ -static int -file_pwrite (void *handle, const void *buf, uint32_t count, uint64_t offset, - uint32_t flags) -{ - struct handle *h = handle; - - while (count > 0) { - ssize_t r = pwrite (h->fd, buf, count, offset); - if (r == -1) { - nbdkit_error ("pwrite: %m"); - return -1; -...

There's a lot of code in nbdkit-file-plugin which it would be nice to reuse elsewhere. One possible approach (as outlined here) is simply to move the file callbacks (like file.pread, file.pwrite, file.zero etc) to a new mini-library. They can then be consumed by other plugins fairly easily by doing: static void * foo_open (int readonly) { struct fileops *fops; int fd, flags; /*