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ext4: improve handling of conflicting mount options

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If the user explicitly specifies conflicting mount options for
delalloc or dioread_nolock and data=journal, fail the mount, instead
of printing a warning and continuing (since many user's won't look at
dmesg and notice the warning).

Also, print a single warning that data=journal implies that delayed
allocation is not on by default (since it's not supported), and
furthermore that O_DIRECT is not supported.  Improve the text in
Documentation/filesystems/ext4.txt so this is clear there as well.

Similarly, if the dioread_nolock mount option is specified when the
file system block size != PAGE_SIZE, fail the mount instead of
printing a warning message and ignoring the mount option.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This commit is contained in:
Theodore Ts'o 2011-09-03 18:22:38 -04:00
parent 2be4751b21
commit 56889787cf
3 changed files with 37 additions and 24 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
Documentation/filesystems/ext4.txt
View File

@ -160,7 +160,9 @@ noload if the filesystem was not unmounted cleanly,
lead to any number of problems.
data=journal All data are committed into the journal prior to being
written into the main file system.
written into the main file system. Enabling
this mode will disable delayed allocation and
O_DIRECT support.
data=ordered (*) All data are forced directly out to the main file
system prior to its metadata being committed to the
@ -419,8 +421,8 @@ written to the journal first, and then to its final location.
In the event of a crash, the journal can be replayed, bringing both data and
metadata into a consistent state. This mode is the slowest except when data
needs to be read from and written to disk at the same time where it
outperforms all others modes. Currently ext4 does not have delayed
allocation support if this data journalling mode is selected.
outperforms all others modes. Enabling this mode will disable delayed
allocation and O_DIRECT support.
/proc entries
=============

3
fs/ext4/ext4.h
View File

@ -922,6 +922,9 @@ struct ext4_inode_info {
#define EXT4_MOUNT_DISCARD 0x40000000 /* Issue DISCARD requests */
#define EXT4_MOUNT_INIT_INODE_TABLE 0x80000000 /* Initialize uninitialized itables */
#define EXT4_MOUNT2_EXPLICIT_DELALLOC 0x00000001 /* User explicitly
specified delalloc */
#define clear_opt(sb, opt) EXT4_SB(sb)->s_mount_opt &= \
~EXT4_MOUNT_##opt
#define set_opt(sb, opt) EXT4_SB(sb)->s_mount_opt |= \

50
fs/ext4/super.c
View File

@ -1801,6 +1801,7 @@ set_qf_format:
break;
case Opt_nodelalloc:
clear_opt(sb, DELALLOC);
clear_opt2(sb, EXPLICIT_DELALLOC);
break;
case Opt_mblk_io_submit:
set_opt(sb, MBLK_IO_SUBMIT);
@ -1817,6 +1818,7 @@ set_qf_format:
break;
case Opt_delalloc:
set_opt(sb, DELALLOC);
set_opt2(sb, EXPLICIT_DELALLOC);
break;
case Opt_block_validity:
set_opt(sb, BLOCK_VALIDITY);
@ -3224,6 +3226,33 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
&journal_ioprio, NULL, 0))
goto failed_mount;
if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA) {
printk_once(KERN_WARNING "EXT4-fs: Warning: mounting "
"with data=journal disables delayed "
"allocation and O_DIRECT support!\n");
if (test_opt2(sb, EXPLICIT_DELALLOC)) {
ext4_msg(sb, KERN_ERR, "can't mount with "
"both data=journal and delalloc");
goto failed_mount;
}
if (test_opt(sb, DIOREAD_NOLOCK)) {
ext4_msg(sb, KERN_ERR, "can't mount with "
"both data=journal and delalloc");
goto failed_mount;
}
if (test_opt(sb, DELALLOC))
clear_opt(sb, DELALLOC);
}
blocksize = BLOCK_SIZE << le32_to_cpu(es->s_log_block_size);
if (test_opt(sb, DIOREAD_NOLOCK)) {
if (blocksize < PAGE_SIZE) {
ext4_msg(sb, KERN_ERR, "can't mount with "
"dioread_nolock if block size != PAGE_SIZE");
goto failed_mount;
}
}
sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
(test_opt(sb, POSIX_ACL) ? MS_POSIXACL : 0);
@ -3265,8 +3294,6 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
if (!ext4_feature_set_ok(sb, (sb->s_flags & MS_RDONLY)))
goto failed_mount;
blocksize = BLOCK_SIZE << le32_to_cpu(es->s_log_block_size);
if (blocksize < EXT4_MIN_BLOCK_SIZE ||
blocksize > EXT4_MAX_BLOCK_SIZE) {
ext4_msg(sb, KERN_ERR,
@ -3679,25 +3706,6 @@ no_journal:
"available");
}
if (test_opt(sb, DELALLOC) &&
(test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)) {
ext4_msg(sb, KERN_WARNING, "Ignoring delalloc option - "
"requested data journaling mode");
clear_opt(sb, DELALLOC);
}
if (test_opt(sb, DIOREAD_NOLOCK)) {
if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA) {
ext4_msg(sb, KERN_WARNING, "Ignoring dioread_nolock "
"option - requested data journaling mode");
clear_opt(sb, DIOREAD_NOLOCK);
}
if (sb->s_blocksize < PAGE_SIZE) {
ext4_msg(sb, KERN_WARNING, "Ignoring dioread_nolock "
"option - block size is too small");
clear_opt(sb, DIOREAD_NOLOCK);
}
}
err = ext4_setup_system_zone(sb);
if (err) {
ext4_msg(sb, KERN_ERR, "failed to initialize system "