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ext4: Add feature set check helper for mount & remount paths 

A user reported that although his root ext4 filesystem was mounting
fine, other filesystems would not mount, with the:

"Filesystem with huge files cannot be mounted RDWR without CONFIG_LBDAF"

error on his 32-bit box built without CONFIG_LBDAF.  This is because
the test at mount time for this situation was not being re-checked
on remount, and the normal boot process makes an ro->rw transition,
so this was being missed.

Refactor to make a common helper function to test the filesystem
features against the type of mount request (RO vs. RW) so that we 
stay consistent.

Addresses Red-Hat-Bugzilla: #517650

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This commit is contained in:
Eric Sandeen 2009-08-18 00:20:23 -04:00 committed by Theodore Ts'o
parent 38877f4e8d
commit a13fb1a453
1 changed files with 49 additions and 42 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

91
fs/ext4/super.c
View File

@ -2254,6 +2254,49 @@ static struct kobj_type ext4_ktype = {
.release = ext4_sb_release,
};
/*
* Check whether this filesystem can be mounted based on
* the features present and the RDONLY/RDWR mount requested.
* Returns 1 if this filesystem can be mounted as requested,
* 0 if it cannot be.
*/
static int ext4_feature_set_ok(struct super_block *sb, int readonly)
{
if (EXT4_HAS_INCOMPAT_FEATURE(sb, ~EXT4_FEATURE_INCOMPAT_SUPP)) {
ext4_msg(sb, KERN_ERR,
"Couldn't mount because of "
"unsupported optional features (%x)",
(le32_to_cpu(EXT4_SB(sb)->s_es->s_feature_incompat) &
~EXT4_FEATURE_INCOMPAT_SUPP));
return 0;
}
if (readonly)
return 1;
/* Check that feature set is OK for a read-write mount */
if (EXT4_HAS_RO_COMPAT_FEATURE(sb, ~EXT4_FEATURE_RO_COMPAT_SUPP)) {
ext4_msg(sb, KERN_ERR, "couldn't mount RDWR because of "
"unsupported optional features (%x)",
(le32_to_cpu(EXT4_SB(sb)->s_es->s_feature_ro_compat) &
~EXT4_FEATURE_RO_COMPAT_SUPP));
return 0;
}
/*
* Large file size enabled file system can only be mounted
* read-write on 32-bit systems if kernel is built with CONFIG_LBDAF
*/
if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_HUGE_FILE)) {
if (sizeof(blkcnt_t) < sizeof(u64)) {
ext4_msg(sb, KERN_ERR, "Filesystem with huge files "
"cannot be mounted RDWR without "
"CONFIG_LBDAF");
return 0;
}
}
return 1;
}
static int ext4_fill_super(struct super_block *sb, void *data, int silent)
__releases(kernel_lock)
__acquires(kernel_lock)
@ -2275,7 +2318,6 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
unsigned int db_count;
unsigned int i;
int needs_recovery, has_huge_files;
int features;
__u64 blocks_count;
int err;
unsigned int journal_ioprio = DEFAULT_JOURNAL_IOPRIO;
@ -2402,39 +2444,9 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
* previously didn't change the revision level when setting the flags,
* so there is a chance incompat flags are set on a rev 0 filesystem.
*/
features = EXT4_HAS_INCOMPAT_FEATURE(sb, ~EXT4_FEATURE_INCOMPAT_SUPP);
if (features) {
ext4_msg(sb, KERN_ERR,
"Couldn't mount because of "
"unsupported optional features (%x)",
(le32_to_cpu(EXT4_SB(sb)->s_es->s_feature_incompat) &
~EXT4_FEATURE_INCOMPAT_SUPP));
if (!ext4_feature_set_ok(sb, (sb->s_flags & MS_RDONLY)))
goto failed_mount;
}
features = EXT4_HAS_RO_COMPAT_FEATURE(sb, ~EXT4_FEATURE_RO_COMPAT_SUPP);
if (!(sb->s_flags & MS_RDONLY) && features) {
ext4_msg(sb, KERN_ERR,
"Couldn't mount RDWR because of "
"unsupported optional features (%x)",
(le32_to_cpu(EXT4_SB(sb)->s_es->s_feature_ro_compat) &
~EXT4_FEATURE_RO_COMPAT_SUPP));
goto failed_mount;
}
has_huge_files = EXT4_HAS_RO_COMPAT_FEATURE(sb,
EXT4_FEATURE_RO_COMPAT_HUGE_FILE);
if (has_huge_files) {
/*
* Large file size enabled file system can only be
* mount if kernel is build with CONFIG_LBDAF
*/
if (sizeof(root->i_blocks) < sizeof(u64) &&
!(sb->s_flags & MS_RDONLY)) {
ext4_msg(sb, KERN_ERR, "Filesystem with huge "
"files cannot be mounted read-write "
"without CONFIG_LBDAF");
goto failed_mount;
}
}
blocksize = BLOCK_SIZE << le32_to_cpu(es->s_log_block_size);
if (blocksize < EXT4_MIN_BLOCK_SIZE ||
@ -2470,6 +2482,8 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
}
}
has_huge_files = EXT4_HAS_RO_COMPAT_FEATURE(sb,
EXT4_FEATURE_RO_COMPAT_HUGE_FILE);
sbi->s_bitmap_maxbytes = ext4_max_bitmap_size(sb->s_blocksize_bits,
has_huge_files);
sb->s_maxbytes = ext4_max_size(sb->s_blocksize_bits, has_huge_files);
@ -3485,18 +3499,11 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data)
if (sbi->s_journal)
ext4_mark_recovery_complete(sb, es);
} else {
int ret;
if ((ret = EXT4_HAS_RO_COMPAT_FEATURE(sb,
~EXT4_FEATURE_RO_COMPAT_SUPP))) {
ext4_msg(sb, KERN_WARNING, "couldn't "
"remount RDWR because of unsupported "
"optional features (%x)",
(le32_to_cpu(sbi->s_es->s_feature_ro_compat) &
~EXT4_FEATURE_RO_COMPAT_SUPP));
/* Make sure we can mount this feature set readwrite */
if (!ext4_feature_set_ok(sb, 0)) {
err = -EROFS;
goto restore_opts;
}
/*
* Make sure the group descriptor checksums
* are sane. If they aren't, refuse to remount r/w.