* [RFC] [PATCHv2 2/2] Add aal_device_discard() function and implement it for file-based device.
2014-05-11 9:33 [RFC] [PATCHv2 0/2] libaal: add device "discard" operation Ivan Shapovalov
2014-05-11 9:33 ` [RFC] [PATCHv2 1/2] configure.in: check for fallocate() and related headers Ivan Shapovalov
@ 2014-05-11 9:33 ` Ivan Shapovalov
1 sibling, 0 replies; 3+ messages in thread
From: Ivan Shapovalov @ 2014-05-11 9:33 UTC (permalink / raw)
To: reiserfs-devel; +Cc: Ivan Shapovalov
Internally, ioctl(BLKDISCARD) or fallocate(FALLOC_FL_PUNCH_HOLE) is used
depending on whether the file is actually a block device.
Signed-off-by: Ivan Shapovalov <intelfx100@gmail.com>
---
include/aal/device.h | 4 +++
include/aal/types.h | 3 +++
src/device.c | 14 ++++++++++
src/file.c | 74 ++++++++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 95 insertions(+)
diff --git a/include/aal/device.h b/include/aal/device.h
index 535fb79..c1ea19d 100644
--- a/include/aal/device.h
+++ b/include/aal/device.h
@@ -22,6 +22,10 @@ extern errno_t aal_device_reopen(aal_device_t *device,
uint32_t blksize,
int flags);
+extern errno_t aal_device_discard(aal_device_t *device,
+ blk_t block,
+ count_t count);
+
extern errno_t aal_device_write(aal_device_t *device,
void *buff, blk_t block,
count_t count);
diff --git a/include/aal/types.h b/include/aal/types.h
index e26edda..5348505 100644
--- a/include/aal/types.h
+++ b/include/aal/types.h
@@ -203,6 +203,9 @@ struct aal_device_ops {
errno_t (*write) (aal_device_t *,
void *, blk_t, count_t);
+ errno_t (*discard) (aal_device_t *,
+ blk_t, count_t);
+
errno_t (*sync) (aal_device_t *);
errno_t (*equals) (aal_device_t *,
diff --git a/src/device.c b/src/device.c
index fe0a539..c5261f8 100644
--- a/src/device.c
+++ b/src/device.c
@@ -114,6 +114,20 @@ errno_t aal_device_write(
return device->ops->write(device, buff, block, count);
}
+/* Performs discard operation on specified device. Actualqy it calls corresponding
+ operation (discard) from assosiated with device operations. Returns error code,
+ see types.h for more detailed description of errno_t. */
+errno_t aal_device_discard(
+ aal_device_t *device, /* device instance we will discard */
+ blk_t block, /* block we will begin discarding from */
+ count_t count) /* number of blocks to be discarded */
+{
+ aal_assert("intelfx-1", device != NULL);
+
+ aal_device_check_routine(device, discard, return -EINVAL);
+ return device->ops->discard(device, block, count);
+}
+
/* Performs sync operation on specified device. Actualy it calls corresponding
operation (sync) from assosiated with device operations. Returns error code,
see types.h for more detailed description of errno_t. */
diff --git a/src/file.c b/src/file.c
index 451c5d4..dd36e3a 100644
--- a/src/file.c
+++ b/src/file.c
@@ -6,6 +6,10 @@
#ifndef ENABLE_MINIMAL
+#ifndef _GNU_SOURCE
+# define _GNU_SOURCE
+#endif
+
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
@@ -18,9 +22,22 @@
#include <sys/stat.h>
#include <sys/ioctl.h>
+#ifdef HAVE_LINUX_FALLOC_H
+# include <linux/falloc.h>
+#endif
+
+#ifdef HAVE_LINUX_TYPES_H
+# include <linux/types.h>
+#endif
+
/* BLKGETSIZE & BLKGETSIZE64 defines: */
#include <sys/mount.h>
+/* BLKDISCARD define: */
+#if defined(__linux__) && !defined(BLKDISCARD)
+# define BLKDISCARD _IO(0x12,119)
+#endif
+
#include <aal/libaal.h>
/* Function for saving last error message into device assosiated buffer */
@@ -160,6 +177,62 @@ static errno_t file_write(
return 0;
}
+/* Handler for "discard" operation for use with file device. See below for
+ understanding where it is used. */
+static errno_t file_discard(
+ aal_device_t *device, /* file device to discard */
+ blk_t block, /* start position for discarding */
+ count_t count) /* number of blocks to be discarded */
+{
+ struct stat st;
+ int ret;
+
+ if (!device)
+ return -EINVAL;
+
+ /* Stat the file */
+ if(stat(device->name, &st) != 0) {
+ file_error(device);
+ return errno;
+ }
+
+ /* Discard or punch hole depending on whether this is a block device */
+ if (S_ISBLK(st.st_mode)) {
+#ifdef BLKDISCARD
+ __u64 range[2];
+
+ range[0] = (__u64)block * device->blksize;
+ range[1] = (__u64)count * device->blksize;
+
+ ret = ioctl(*((int *)device->entity), BLKDISCARD, &range);
+#else
+ errno = EOPNOTSUPP;
+ ret = -1;
+#endif
+ } else {
+#if defined(HAVE_FALLOCATE) && defined(FALLOC_FL_PUNCH_HOLE)
+ off_t blk, len;
+
+ blk = (off_t)block * device->blksize;
+ len = (off_t)count * device->blksize;
+
+ ret = fallocate(*((int *)device->entity),
+ FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
+ blk, len);
+#else
+ errno = EOPNOTSUPP;
+ ret = -1;
+#endif
+ }
+
+ if (ret != 0) {
+ file_error(device);
+ return errno;
+ }
+
+ return 0;
+}
+
/* Handler for "sync" operation for use with file device. See bellow for
understanding where it is used. */
static errno_t file_sync(
@@ -245,6 +318,7 @@ struct aal_device_ops file_ops = {
.close = file_close, /* handler for "create" operation */
.read = file_read, /* handler for "read" operation */
.write = file_write, /* handler for "write" operation */
+ .discard = file_discard, /* handler for "discard" operation */
.sync = file_sync, /* handler for "sync" operation */
.equals = file_equals, /* handler for comparing two devices */
.len = file_len /* handler for length obtaining */
--
1.9.2
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