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Merge "fs_mgr: Support filesystem labels in fstab"

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Elliott Hughes 2015-01-23 18:11:26 +00:00 committed by Gerrit Code Review
commit 4e0bdd1034
1 changed files with 91 additions and 0 deletions
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91
fs_mgr/fs_mgr.c
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@ -28,6 +28,9 @@
#include <libgen.h>
#include <time.h>
#include <sys/swap.h>
#include <dirent.h>
#include <ext4.h>
#include <ext4_sb.h>
#include <linux/loop.h>
#include <private/android_filesystem_config.h>
@ -325,6 +328,83 @@ static int mount_with_alternatives(struct fstab *fstab, int start_idx, int *end_
return 0;
}
static int translate_ext_labels(struct fstab_rec *rec)
{
DIR *blockdir = NULL;
struct dirent *ent;
char *label;
size_t label_len;
int ret = -1;
if (strncmp(rec->blk_device, "LABEL=", 6))
return 0;
label = rec->blk_device + 6;
label_len = strlen(label);
if (label_len > 16) {
ERROR("FS label is longer than allowed by filesystem\n");
goto out;
}
blockdir = opendir("/dev/block");
if (!blockdir) {
ERROR("couldn't open /dev/block\n");
goto out;
}
while ((ent = readdir(blockdir))) {
int fd;
char super_buf[1024];
struct ext4_super_block *sb;
if (ent->d_type != DT_BLK)
continue;
fd = openat(dirfd(blockdir), ent->d_name, O_RDONLY);
if (fd < 0) {
ERROR("Cannot open block device /dev/block/%s\n", ent->d_name);
goto out;
}
if (TEMP_FAILURE_RETRY(lseek(fd, 1024, SEEK_SET)) < 0 ||
TEMP_FAILURE_RETRY(read(fd, super_buf, 1024)) != 1024) {
/* Probably a loopback device or something else without a readable
* superblock.
*/
close(fd);
continue;
}
sb = (struct ext4_super_block *)super_buf;
if (sb->s_magic != EXT4_SUPER_MAGIC) {
INFO("/dev/block/%s not ext{234}\n", ent->d_name);
continue;
}
if (!strncmp(label, sb->s_volume_name, label_len)) {
char *new_blk_device;
if (asprintf(&new_blk_device, "/dev/block/%s", ent->d_name) < 0) {
ERROR("Could not allocate block device string\n");
goto out;
}
INFO("resolved label %s to %s\n", rec->blk_device, new_blk_device);
free(rec->blk_device);
rec->blk_device = new_blk_device;
ret = 0;
break;
}
}
out:
closedir(blockdir);
return ret;
}
/* When multiple fstab records share the same mount_point, it will
* try to mount each one in turn, and ignore any duplicates after a
* first successful mount.
@ -356,6 +436,17 @@ int fs_mgr_mount_all(struct fstab *fstab)
continue;
}
/* Translate LABEL= file system labels into block devices */
if (!strcmp(fstab->recs[i].fs_type, "ext2") ||
!strcmp(fstab->recs[i].fs_type, "ext3") ||
!strcmp(fstab->recs[i].fs_type, "ext4")) {
int tret = translate_ext_labels(&fstab->recs[i]);
if (tret < 0) {
ERROR("Could not translate label to block device\n");
continue;
}
}
if (fstab->recs[i].fs_mgr_flags & MF_WAIT) {
wait_for_file(fstab->recs[i].blk_device, WAIT_TIMEOUT);
}