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authorJan Kara <jack@suse.cz>2013-07-25 16:15:16 +0200
committerJan Kara <jack@suse.cz>2013-07-31 22:14:51 +0200
commite729eac6f65e11c5f03b09adcc84bd5bcb230467 (patch)
tree0165a2b95c0262c2df0510b50f8e445241672af1
parentd759bfa4e7919b89357de50a2e23817079889195 (diff)
udf: Refuse RW mount of the filesystem instead of making it RO
Refuse RW mount of udf filesystem. So far we just silently changed it to RO mount but when the media is writeable, block layer won't notice this change and thus will think device is used RW and will block eject button of the drive. That is unexpected by users because for non-writeable media eject button works just fine. Userspace mount(8) command handles this just fine and retries mounting with MS_RDONLY set so userspace shouldn't see any regression. Plus any tool mounting udf is likely confronted with the case of read-only media where block layer already refuses to mount the filesystem without MS_RDONLY set so our behavior shouldn't be anything new for it. Reported-by: Hui Wang <hui.wang@canonical.com> Signed-off-by: Jan Kara <jack@suse.cz>
-rw-r--r--fs/udf/super.c42
1 files changed, 24 insertions, 18 deletions
diff --git a/fs/udf/super.c b/fs/udf/super.c
index c68da0dac2c5..839a2bad7f45 100644
--- a/fs/udf/super.c
+++ b/fs/udf/super.c
@@ -630,6 +630,12 @@ static int udf_remount_fs(struct super_block *sb, int *flags, char *options)
struct udf_sb_info *sbi = UDF_SB(sb);
int error = 0;
+ if (sbi->s_lvid_bh) {
+ int write_rev = le16_to_cpu(udf_sb_lvidiu(sbi)->minUDFWriteRev);
+ if (write_rev > UDF_MAX_WRITE_VERSION && !(*flags & MS_RDONLY))
+ return -EACCES;
+ }
+
uopt.flags = sbi->s_flags;
uopt.uid = sbi->s_uid;
uopt.gid = sbi->s_gid;
@@ -649,12 +655,6 @@ static int udf_remount_fs(struct super_block *sb, int *flags, char *options)
sbi->s_dmode = uopt.dmode;
write_unlock(&sbi->s_cred_lock);
- if (sbi->s_lvid_bh) {
- int write_rev = le16_to_cpu(udf_sb_lvidiu(sbi)->minUDFWriteRev);
- if (write_rev > UDF_MAX_WRITE_VERSION)
- *flags |= MS_RDONLY;
- }
-
if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
goto out_unlock;
@@ -1284,16 +1284,18 @@ static int udf_load_partdesc(struct super_block *sb, sector_t block)
goto out_bh;
}
} else {
+ /*
+ * If we have a partition with virtual map, we don't handle
+ * writing to it (we overwrite blocks instead of relocating
+ * them).
+ */
+ if (!(sb->s_flags & MS_RDONLY)) {
+ ret = -EACCES;
+ goto out_bh;
+ }
ret = udf_load_vat(sb, i, type1_idx);
if (ret < 0)
goto out_bh;
- /*
- * Mark filesystem read-only if we have a partition with
- * virtual map since we don't handle writing to it (we
- * overwrite blocks instead of relocating them).
- */
- sb->s_flags |= MS_RDONLY;
- pr_notice("Filesystem marked read-only because writing to pseudooverwrite partition is not implemented\n");
}
ret = 0;
out_bh:
@@ -2103,8 +2105,11 @@ static int udf_fill_super(struct super_block *sb, void *options, int silent)
UDF_MAX_READ_VERSION);
ret = -EINVAL;
goto error_out;
- } else if (minUDFWriteRev > UDF_MAX_WRITE_VERSION)
- sb->s_flags |= MS_RDONLY;
+ } else if (minUDFWriteRev > UDF_MAX_WRITE_VERSION &&
+ !(sb->s_flags & MS_RDONLY)) {
+ ret = -EACCES;
+ goto error_out;
+ }
sbi->s_udfrev = minUDFWriteRev;
@@ -2121,9 +2126,10 @@ static int udf_fill_super(struct super_block *sb, void *options, int silent)
}
if (sbi->s_partmaps[sbi->s_partition].s_partition_flags &
- UDF_PART_FLAG_READ_ONLY) {
- pr_notice("Partition marked readonly; forcing readonly mount\n");
- sb->s_flags |= MS_RDONLY;
+ UDF_PART_FLAG_READ_ONLY &&
+ !(sb->s_flags & MS_RDONLY)) {
+ ret = -EACCES;
+ goto error_out;
}
if (udf_find_fileset(sb, &fileset, &rootdir)) {