ext4: improve handling of conflincting mount options

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>

diff --git a/Documentation/filesystems/ext4.txt b/Documentation/filesystems/ext4.txt
index 232a575a0c4857249edc5aa76a235ce4e258082f..168242b5c045ff6542907dedd11146af6f4e234f 100644 (file)
--- a/Documentation/filesystems/ext4.txt
+++ b/Documentation/filesystems/ext4.txt
@@ -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
 =============

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index e717dfd2f2b4b2e1871e4c66452202b89191ba61..062c66862f43b75fd2433bfed28527aeb14d2d04 100644 (file)
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -917,6 +917,9 @@ 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 |= \

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 44d0c8db2239f958d08d4de4462cdc6ca936d1e1..c3e3a803d0459e2c5b6dce86a41a414dfc998ae6 100644 (file)
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -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 +3226,31 @@ 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);
+       }
+       if (test_opt(sb, DIOREAD_NOLOCK)) {
+               if (sb->s_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);
 
@@ -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 "