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ext2fs: add readahead method to improve scanning
[tools/e2fsprogs.git] / lib / ext2fs / unix_io.c
index 1df1fdd..eb8e359 100644 (file)
  * %End-Header%
  */
 
+#define _XOPEN_SOURCE 600
+#define _DARWIN_C_SOURCE
+#define _FILE_OFFSET_BITS 64
 #define _LARGEFILE_SOURCE
 #define _LARGEFILE64_SOURCE
+#ifndef _GNU_SOURCE
 #define _GNU_SOURCE
+#endif
 
+#include "config.h"
 #include <stdio.h>
 #include <string.h>
 #if HAVE_UNISTD_H
@@ -32,6 +38,9 @@
 #ifdef __linux__
 #include <sys/utsname.h>
 #endif
+#if HAVE_SYS_TYPES_H
+#include <sys/types.h>
+#endif
 #ifdef HAVE_SYS_IOCTL_H
 #include <sys/ioctl.h>
 #endif
 #if HAVE_SYS_STAT_H
 #include <sys/stat.h>
 #endif
-#if HAVE_SYS_TYPES_H
-#include <sys/types.h>
-#endif
 #if HAVE_SYS_RESOURCE_H
 #include <sys/resource.h>
 #endif
+#if HAVE_LINUX_FALLOC_H
+#include <linux/falloc.h>
+#endif
 
 #if defined(__linux__) && defined(_IO) && !defined(BLKROGET)
 #define BLKROGET   _IO(0x12, 94) /* Get read-only status (0 = read_write).  */
 #endif
 
-#if defined(__linux__) && defined(_IO) && !defined(BLKSSZGET)
-#define BLKSSZGET  _IO(0x12,104)/* get block device sector size */
-#endif
-
 #undef ALIGN_DEBUG
 
 #include "ext2_fs.h"
          if ((struct)->magic != (code)) return (code)
 
 struct unix_cache {
-       char            *buf;
-       unsigned long   block;
-       int             access_time;
-       unsigned        dirty:1;
-       unsigned        in_use:1;
+       char                    *buf;
+       unsigned long long      block;
+       int                     access_time;
+       unsigned                dirty:1;
+       unsigned                in_use:1;
 };
 
 #define CACHE_SIZE 8
@@ -115,6 +120,10 @@ static errcode_t unix_read_blk64(io_channel channel, unsigned long long block,
                               int count, void *data);
 static errcode_t unix_write_blk64(io_channel channel, unsigned long long block,
                                int count, const void *data);
+static errcode_t unix_discard(io_channel channel, unsigned long long block,
+                             unsigned long long count);
+static errcode_t unix_readahead(io_channel channel, unsigned long block,
+                               int count);
 
 static struct struct_io_manager struct_unix_manager = {
        EXT2_ET_MAGIC_IO_MANAGER,
@@ -130,6 +139,8 @@ static struct struct_io_manager struct_unix_manager = {
        unix_get_stats,
        unix_read_blk64,
        unix_write_blk64,
+       unix_discard,
+       unix_readahead,
 };
 
 io_manager unix_io_manager = &struct_unix_manager;
@@ -156,12 +167,13 @@ static errcode_t unix_get_stats(io_channel channel, io_stats *stats)
 static errcode_t raw_read_blk(io_channel channel,
                              struct unix_private_data *data,
                              unsigned long long block,
-                             int count, void *buf)
+                             int count, void *bufv)
 {
        errcode_t       retval;
        ssize_t         size;
        ext2_loff_t     location;
        int             actual = 0;
+       unsigned char   *buf = bufv;
 
        size = (count < 0) ? -count : count * channel->block_size;
        data->io_stats.bytes_read += size;
@@ -170,8 +182,9 @@ static errcode_t raw_read_blk(io_channel channel,
                retval = errno ? errno : EXT2_ET_LLSEEK_FAILED;
                goto error_out;
        }
-       if ((data->align == 0) ||
-           ((IS_ALIGNED(buf, data->align)) && IS_ALIGNED(size, data->align))) {
+       if ((channel->align == 0) ||
+           (IS_ALIGNED(buf, channel->align) &&
+            IS_ALIGNED(size, channel->align))) {
                actual = read(data->dev, buf, size);
                if (actual != size) {
                short_read:
@@ -216,12 +229,13 @@ error_out:
 static errcode_t raw_write_blk(io_channel channel,
                               struct unix_private_data *data,
                               unsigned long long block,
-                              int count, const void *buf)
+                              int count, const void *bufv)
 {
        ssize_t         size;
        ext2_loff_t     location;
        int             actual = 0;
        errcode_t       retval;
+       const unsigned char *buf = bufv;
 
        if (count == 1)
                size = channel->block_size;
@@ -239,8 +253,9 @@ static errcode_t raw_write_blk(io_channel channel,
                goto error_out;
        }
 
-       if ((data->align == 0) ||
-           ((IS_ALIGNED(buf, data->align)) && IS_ALIGNED(size, data->align))) {
+       if ((channel->align == 0) ||
+           (IS_ALIGNED(buf, channel->align) &&
+            IS_ALIGNED(size, channel->align))) {
                actual = write(data->dev, buf, size);
                if (actual != size) {
                short_write:
@@ -307,16 +322,14 @@ static errcode_t alloc_cache(io_channel channel,
                cache->in_use = 0;
                if (cache->buf)
                        ext2fs_free_mem(&cache->buf);
-               retval = ext2fs_get_memalign(channel->block_size,
-                                            data->align, &cache->buf);
+               retval = io_channel_alloc_buf(channel, 0, &cache->buf);
                if (retval)
                        return retval;
        }
-       if (data->align) {
+       if (channel->align) {
                if (data->bounce)
                        ext2fs_free_mem(&data->bounce);
-               retval = ext2fs_get_memalign(channel->block_size, data->align,
-                                            &data->bounce);
+               retval = io_channel_alloc_buf(channel, 0, &data->bounce);
        }
        return retval;
 }
@@ -422,13 +435,52 @@ static errcode_t flush_cached_blocks(io_channel channel,
 }
 #endif /* NO_IO_CACHE */
 
+#ifdef __linux__
+#ifndef BLKDISCARDZEROES
+#define BLKDISCARDZEROES _IO(0x12,124)
+#endif
+#endif
+
+int ext2fs_open_file(const char *pathname, int flags, mode_t mode)
+{
+       if (mode)
+#if defined(HAVE_OPEN64) && !defined(__OSX_AVAILABLE_BUT_DEPRECATED)
+               return open64(pathname, flags, mode);
+       else
+               return open64(pathname, flags);
+#else
+               return open(pathname, flags, mode);
+       else
+               return open(pathname, flags);
+#endif
+}
+
+int ext2fs_stat(const char *path, ext2fs_struct_stat *buf)
+{
+#if defined(HAVE_FSTAT64) && !defined(__OSX_AVAILABLE_BUT_DEPRECATED)
+       return stat64(path, buf);
+#else
+       return stat(path, buf);
+#endif
+}
+
+int ext2fs_fstat(int fd, ext2fs_struct_stat *buf)
+{
+#if defined(HAVE_FSTAT64) && !defined(__OSX_AVAILABLE_BUT_DEPRECATED)
+       return fstat64(fd, buf);
+#else
+       return fstat(fd, buf);
+#endif
+}
+
 static errcode_t unix_open(const char *name, int flags, io_channel *channel)
 {
        io_channel      io = NULL;
        struct unix_private_data *data = NULL;
        errcode_t       retval;
-       int             open_flags;
-       struct stat     st;
+       int             open_flags, zeroes = 0;
+       int             f_nocache = 0;
+       ext2fs_struct_stat st;
 #ifdef __linux__
        struct          utsname ut;
 #endif
@@ -437,7 +489,7 @@ static errcode_t unix_open(const char *name, int flags, io_channel *channel)
                return EXT2_ET_BAD_DEVICE_NAME;
        retval = ext2fs_get_mem(sizeof(struct struct_io_channel), &io);
        if (retval)
-               return retval;
+               goto cleanup;
        memset(io, 0, sizeof(struct struct_io_channel));
        io->magic = EXT2_ET_MAGIC_IO_CHANNEL;
        retval = ext2fs_get_mem(sizeof(struct unix_private_data), &data);
@@ -463,25 +515,49 @@ static errcode_t unix_open(const char *name, int flags, io_channel *channel)
        open_flags = (flags & IO_FLAG_RW) ? O_RDWR : O_RDONLY;
        if (flags & IO_FLAG_EXCLUSIVE)
                open_flags |= O_EXCL;
-       if (flags & IO_FLAG_DIRECT_IO)
+#if defined(O_DIRECT)
+       if (flags & IO_FLAG_DIRECT_IO) {
                open_flags |= O_DIRECT;
+               io->align = ext2fs_get_dio_alignment(data->dev);
+       }
+#elif defined(F_NOCACHE)
+       if (flags & IO_FLAG_DIRECT_IO) {
+               f_nocache = F_NOCACHE;
+               io->align = 4096;
+       }
+#endif
        data->flags = flags;
 
-#ifdef HAVE_OPEN64
-       data->dev = open64(io->name, open_flags);
-#else
-       data->dev = open(io->name, open_flags);
-#endif
+       data->dev = ext2fs_open_file(io->name, open_flags, 0);
        if (data->dev < 0) {
                retval = errno;
                goto cleanup;
        }
+       if (f_nocache) {
+               if (fcntl(data->dev, f_nocache, 1) < 0) {
+                       retval = errno;
+                       goto cleanup;
+               }
+       }
 
-#ifdef BLKSSZGET
-       if (flags & IO_FLAG_DIRECT_IO) {
-               if (ioctl(data->dev, BLKSSZGET, &data->align) != 0)
-                       data->align = io->block_size;
+       /*
+        * If the device is really a block device, then set the
+        * appropriate flag, otherwise we can set DISCARD_ZEROES flag
+        * because we are going to use punch hole instead of discard
+        * and if it succeed, subsequent read from sparse area returns
+        * zero.
+        */
+       if (ext2fs_stat(io->name, &st) == 0) {
+               if (S_ISBLK(st.st_mode))
+                       io->flags |= CHANNEL_FLAGS_BLOCK_DEVICE;
+               else
+                       io->flags |= CHANNEL_FLAGS_DISCARD_ZEROES;
        }
+
+#ifdef BLKDISCARDZEROES
+       ioctl(data->dev, BLKDISCARDZEROES, &zeroes);
+       if (zeroes)
+               io->flags |= CHANNEL_FLAGS_DISCARD_ZEROES;
 #endif
 
 #if defined(__CYGWIN__) || defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
@@ -489,7 +565,8 @@ static errcode_t unix_open(const char *name, int flags, io_channel *channel)
         * Some operating systems require that the buffers be aligned,
         * regardless of O_DIRECT
         */
-       data->align = 512;
+       if (!io->align)
+               io->align = 512;
 #endif
 
 
@@ -531,7 +608,7 @@ static errcode_t unix_open(const char *name, int flags, io_channel *channel)
             (ut.release[2] == '4') && (ut.release[3] == '.') &&
             (ut.release[4] == '1') && (ut.release[5] >= '0') &&
             (ut.release[5] < '8')) &&
-           (fstat(data->dev, &st) == 0) &&
+           (ext2fs_stat(io->name, &st) == 0) &&
            (S_ISBLK(st.st_mode))) {
                struct rlimit   rlim;
 
@@ -748,6 +825,20 @@ static errcode_t unix_write_blk64(io_channel channel, unsigned long long block,
 #endif /* NO_IO_CACHE */
 }
 
+static errcode_t unix_readahead(io_channel channel, unsigned long block,
+                               int count)
+{
+#ifdef POSIX_FADV_WILLNEED
+       struct unix_private_data *data;
+
+       data = (struct unix_private_data *)channel->private_data;
+       posix_fadvise(data->dev, (ext2_loff_t)block * channel->block_size,
+                     (ext2_loff_t)count * channel->block_size,
+                     POSIX_FADV_WILLNEED);
+#endif
+       return 0;
+}
+
 static errcode_t unix_write_blk(io_channel channel, unsigned long block,
                                int count, const void *buf)
 {
@@ -765,7 +856,7 @@ static errcode_t unix_write_byte(io_channel channel, unsigned long offset,
        data = (struct unix_private_data *) channel->private_data;
        EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
 
-       if (data->align != 0) {
+       if (channel->align != 0) {
 #ifdef ALIGN_DEBUG
                printf("unix_write_byte: O_DIRECT fallback\n");
 #endif
@@ -834,3 +925,51 @@ static errcode_t unix_set_option(io_channel channel, const char *option,
        }
        return EXT2_ET_INVALID_ARGUMENT;
 }
+
+#if defined(__linux__) && !defined(BLKDISCARD)
+#define BLKDISCARD             _IO(0x12,119)
+#endif
+
+static errcode_t unix_discard(io_channel channel, unsigned long long block,
+                             unsigned long long count)
+{
+       struct unix_private_data *data;
+       __uint64_t      range[2];
+       int             ret;
+
+       EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
+       data = (struct unix_private_data *) channel->private_data;
+       EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
+
+       if (channel->flags & CHANNEL_FLAGS_BLOCK_DEVICE) {
+#ifdef BLKDISCARD
+               range[0] = (__uint64_t)(block) * channel->block_size;
+               range[1] = (__uint64_t)(count) * channel->block_size;
+
+               ret = ioctl(data->dev, BLKDISCARD, &range);
+#else
+               goto unimplemented;
+#endif
+       } else {
+#if defined(HAVE_FALLOCATE) && defined(FALLOC_FL_PUNCH_HOLE)
+               /*
+                * If we are not on block device, try to use punch hole
+                * to reclaim free space.
+                */
+               ret = fallocate(data->dev,
+                               FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
+                               (off_t)(block) * channel->block_size,
+                               (off_t)(count) * channel->block_size);
+#else
+               goto unimplemented;
+#endif
+       }
+       if (ret < 0) {
+               if (errno == EOPNOTSUPP)
+                       goto unimplemented;
+               return errno;
+       }
+       return 0;
+unimplemented:
+       return EXT2_ET_UNIMPLEMENTED;
+}