search for: can_punch_hole

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

...++ b/plugins/file/file.c @@ -33,6 +33,7 @@ #include <config.h> +#include <stdbool.h> #include <stdio.h> #include <stdlib.h> #include <string.h> @@ -118,6 +119,8 @@ file_config_complete (void) /* The per-connection handle. */ struct handle { int fd; + bool can_punch_hole; + bool can_zero_range; }; /* Create the per-connection handle. */ @@ -146,6 +149,18 @@ file_open (int 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_zer...

...++ b/plugins/file/file.c @@ -33,6 +33,7 @@ #include <config.h> +#include <stdbool.h> #include <stdio.h> #include <stdlib.h> #include <string.h> @@ -118,6 +119,8 @@ file_config_complete (void) /* The per-connection handle. */ struct handle { int fd; + bool can_punch_hole; + bool can_zero_range; }; /* Create the per-connection handle. */ @@ -146,6 +149,18 @@ file_open (int 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_zer...

...++ b/plugins/file/file.c @@ -33,6 +33,7 @@ #include <config.h> +#include <stdbool.h> #include <stdio.h> #include <stdlib.h> #include <string.h> @@ -118,6 +119,8 @@ file_config_complete (void) /* The per-connection handle. */ struct handle { int fd; + bool can_punch_hole; + bool can_zero_range; }; /* Create the per-connection handle. */ @@ -146,6 +149,18 @@ file_open (int 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_zer...

...@@ -35,6 +35,7 @@ #include <stdio.h> #include <stdlib.h> +#include <stdbool.h> #include <string.h> #include <fcntl.h> #include <unistd.h> @@ -118,6 +119,8 @@ file_config_complete (void) /* The per-connection handle. */ struct handle { int fd; + bool can_punch_hole; + bool can_zero_range; }; /* Create the per-connection handle. */ @@ -146,6 +149,18 @@ file_open (int 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_zer...

...manual writing > > - trim changed to: > 1. If we can punch hole, try PUNCH_HOLE > 2. Succeed Seems reasonable from the description. > @@ -118,6 +119,8 @@ file_config_complete (void) > /* The per-connection handle. */ > struct handle { > int fd; > + bool can_punch_hole; > + bool can_zero_range; Would it be better to make these tri-state rather than merely bool? (Indeterminate, supported, known to fail) > }; > > /* Create the per-connection handle. */ > @@ -146,6 +149,18 @@ file_open (int readonly) > return NULL; > } >...

...inux 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 sector size. - initialize h->can_* properly. Before they were uninitialized if FALLOC_FL_* macros were not defined. - Use new h->can_punch_hole in file_can_trim, so now we report the actual capability once we detected it. - Use h->can_punch_hole in file_trim, so we try only once if the operation is not supported. v1 was here: https://www.redhat.com/archives/libguestfs/2018-July/msg00084.html Nir Soffer (4): file: Avoid unsupport...

...+#include <sys/types.h> + +/* Either use this as the per-connection handle, or it must appear as + * the first member of the per-connection handle. Don’t access these + * fields directly from your plugin. + */ +struct fileops { + int fd; + int sector_size; + bool is_block_device; + bool can_punch_hole; + bool can_zero_range; + bool can_fallocate; + bool can_zeroout; +}; + +/* Initialize the fileops struct. ‘fd’ is a file descriptor opened on + * the local file or block device that you want to serve. Call this + * from your .open callback after allocating the handle and setting up + * the fi...

This version addresses comments on v3. Changes since v3: - Finally got spacing right (Eric) - Reorder includes (Richard) - Return 0 or -1 instead of r (Richard) - Add common/include/isaligned.h to Makefile.am (Richard) v3 was here: https://www.redhat.com/archives/libguestfs/2018-August/msg00177.html Nir Soffer (4): file: Avoid unsupported fallocate() calls file: Support zero without

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; /*

...loc.h> /* For FALLOC_FL_* on RHEL, glibc < 2.18 */ +#include <sys/ioctl.h> +#include <linux/fs.h> #include <nbdkit-plugin.h> @@ -116,6 +119,10 @@ file_config_complete (void) /* The per-connection handle. */ struct handle { int fd; + bool is_block_device; + bool can_punch_hole; + bool can_zero_range; + bool can_fallocate; }; /* Create the per-connection handle. */ @@ -123,6 +130,7 @@ static void * file_open (int readonly) { struct handle *h; + struct stat statbuf; int flags; h = malloc (sizeof *h); @@ -144,6 +152,23 @@ file_open (int readonly) re...

...loc.h> /* For FALLOC_FL_* on RHEL, glibc < 2.18 */ +#include <sys/ioctl.h> +#include <linux/fs.h> #include <nbdkit-plugin.h> @@ -116,6 +119,10 @@ file_config_complete (void) /* The per-connection handle. */ struct handle { int fd; + bool is_block_device; + bool can_punch_hole; + bool can_zero_range; + bool can_fallocate; }; /* Create the per-connection handle. */ @@ -123,6 +130,7 @@ static void * file_open (int readonly) { struct handle *h; + struct stat statbuf; int flags; h = malloc (sizeof *h); @@ -144,6 +152,23 @@ file_open (int readonly) re...

This version addresses some of the comments on v2. Changes since v2: - file_zero: Add missing space in function call - is_aligned: Assert that align is indeed a power of 2 - Spelling in commit message Not changed: - Eric commented that spacing was off: https://www.redhat.com/archives/libguestfs/2018-August/msg00113.html but I could not find anything wrong. - Eric asked if ioctl.h will cause

...t; > 1. If we can punch hole, try PUNCH_HOLE > > 2. Succeed > > Seems reasonable from the description. > > > @@ -118,6 +119,8 @@ file_config_complete (void) > > /* The per-connection handle. */ > > struct handle { > > int fd; > > + bool can_punch_hole; > > + bool can_zero_range; > > Would it be better to make these tri-state rather than merely bool? > (Indeterminate, supported, known to fail) > What is the advantage of having tri-state? > > }; > > > > /* Create the per-connection handle. */ > > @...

Needs some work still, see in particular the commit message for patch 3. Rich.

...ffset, off_t len) /* Write zeroes to the file. */ static int -file_zero (void *handle, uint32_t count, uint64_t offset, int may_trim) +file_zero (void *handle, uint32_t count, uint64_t offset, uint32_t flags) { struct handle *h = handle; int r; #ifdef FALLOC_FL_PUNCH_HOLE - if (h->can_punch_hole && may_trim) { + if (h->can_punch_hole && (flags & NBDKIT_FLAG_MAY_TRIM)) { r = do_fallocate (h->fd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, offset, count); if (r == 0) { if (file_debug_zero) nbdkit_debug ("h->c...

...qemu-img. --- plugins/file/file.c | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) diff --git a/plugins/file/file.c b/plugins/file/file.c index 8bb9a2d..aa05492 100644 --- a/plugins/file/file.c +++ b/plugins/file/file.c @@ -121,6 +121,7 @@ struct handle { int fd; bool can_punch_hole; bool can_zero_range; + bool can_fallocate; }; /* Create the per-connection handle. */ @@ -161,6 +162,8 @@ file_open (int readonly) h->can_zero_range = false; #endif + h->can_fallocate = true; + return h; } @@ -297,6 +300,35 @@ file_zero (void *handle, uint32_t count, uin...

...qemu-img. --- plugins/file/file.c | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) diff --git a/plugins/file/file.c b/plugins/file/file.c index 5daab63..a2cea4a 100644 --- a/plugins/file/file.c +++ b/plugins/file/file.c @@ -121,6 +121,7 @@ struct handle { int fd; bool can_punch_hole; bool can_zero_range; + bool can_fallocate; }; /* Create the per-connection handle. */ @@ -161,6 +162,8 @@ file_open (int readonly) h->can_zero_range = false; #endif + h->can_fallocate = true; + return h; } @@ -301,6 +304,35 @@ file_zero (void *handle, uint32_t count, uin...

...nst char *tmpdir = "/var/tmp"; @@ -153,12 +153,6 @@ tmpdisk_config_complete (void) "type=ext4|... The filesystem type.\n" \ "command=<COMMAND> Alternate command instead of mkfs." -struct handle { - int fd; - int64_t size; - bool can_punch_hole; -}; - /* Multi-conn is absolutely unsafe! In this callback it is simply * returning the default value (no multi-conn), that's to make it * clear for future authors. @@ -169,33 +163,6 @@ tmpdisk_can_multi_conn (void *handle) return 0; } -static int -tmpdisk_can_trim (void *handle) -...

...fallocate to zero a range. This is much more efficient than writing zeros > + manually. */ s/is/can be/ (it's two syscalls instead of one, and may not be as efficient as we'd like - but does indeed stand a chance of being more efficient than manual efforts) > + if (h->can_punch_hole && h->can_fallocate) { > + r = do_fallocate (h->fd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, > + offset, count); > + if (r == 0) { > + r = do_fallocate(h->fd, 0, offset, count); > + if (r == 0) > + return 0; > + &g...