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authorTheodore Ts'o <tytso@mit.edu>2011-09-03 18:22:38 -0400
committerTheodore Ts'o <tytso@mit.edu>2011-09-03 18:22:38 -0400
commit56889787cfa77dfd96f0b3a3e6a4f26c2e4a5134 (patch)
tree5fb1be2d593fae0bb1a566397c58dc4f7ce010f2 /Documentation
parent2be4751b21ae1cacb002da48cfc5bf6743fee8c1 (diff)
downloadlinux-56889787cfa77dfd96f0b3a3e6a4f26c2e4a5134.tar.gz
ext4: improve handling of conflicting 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>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/filesystems/ext4.txt8
1 files changed, 5 insertions, 3 deletions
diff --git a/Documentation/filesystems/ext4.txt b/Documentation/filesystems/ext4.txt
index 232a575a0c48..168242b5c045 100644
--- 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
 =============