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| author | Darrick J. Wong <darrick.wong@oracle.com> | 2017-01-10 14:51:52 -0800 |
|---|---|---|
| committer | Darrick J. Wong <darrick.wong@oracle.com> | 2017-07-01 21:40:15 -0700 |
| commit | b304a9479388c321cee17cc1d9d3601c19df0b0b (patch) | |
| tree | ef31538bce59e7c93b3446760d69ca18cb615eeb | |
| parent | fc7cfa00bcdc8b880c7ea99a22796febfaee7f2b (diff) | |
| download | xfs-documentation-b304a9479388c321cee17cc1d9d3601c19df0b0b.tar.gz | |
docs: clarify what the ATTRBIT and ATTR2BIT feature flags do
It would seem that the disk format doesn't actually change depending on
ATTRBIT and ATTR2BIT. The key difference is that ATTR2BIT (without the
'noattr2' mount option) allows di_forkoff to change depending on how
much space the attr fork needs, whereas ATTRBIT (without ATTR2BIT or
the 'attr2' mount option) does not allow di_forkoff to change.
In other words, at least one of the bits must be set if there are
extended attributes, but between the two bits the only difference is a
change in the default di_forkoff adjustment behaviors.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
| -rw-r--r-- | design/XFS_Filesystem_Structure/allocation_groups.asciidoc | 17 |
1 files changed, 12 insertions, 5 deletions
diff --git a/design/XFS_Filesystem_Structure/allocation_groups.asciidoc b/design/XFS_Filesystem_Structure/allocation_groups.asciidoc index 51ca57d..68f934a 100644 --- a/design/XFS_Filesystem_Structure/allocation_groups.asciidoc +++ b/design/XFS_Filesystem_Structure/allocation_groups.asciidoc @@ -174,7 +174,13 @@ indicate features introduced over time. If the value of the lower nibble is >= [options="header"] |===== | Flag | Description -| +XFS_SB_VERSION_ATTRBIT+ | Set if any inode have extended attributes. +| +XFS_SB_VERSION_ATTRBIT+ | +Set if any inode have extended attributes. If this bit is set; the ++XFS_SB_VERSION2_ATTR2BIT+ is not set; and the +attr2+ mount flag is not +specified, the +di_forkoff+ inode field will not be dynamically adjusted. +See the section about xref:Extended_Attribute_Versions[extended attribute +versions] for more information. + | +XFS_SB_VERSION_NLINKBIT+ | Set if any inodes use 32-bit di_nlink values. | +XFS_SB_VERSION_QUOTABIT+ | Quotas are enabled on the filesystem. This @@ -335,10 +341,11 @@ performance. The global free space and inode counts are only updated in the primary superblock when the filesystem is cleanly unmounted. | +XFS_SB_VERSION2_ATTR2BIT+ | -Extended attributes version 2. Making a filesystem with this optimises the inode -layout of extended attributes. See the section about -xref:Extended_Attribute_Versions[extended attribute versions] for more -information. +Extended attributes version 2. Making a filesystem with this optimises the +inode layout of extended attributes. If this bit is set and the +noattr2+ +mount flag is not specified, the +di_forkoff+ inode field will be dynamically +adjusted. See the section about xref:Extended_Attribute_Versions[extended +attribute versions] for more information. | +XFS_SB_VERSION2_PARENTBIT+ | Parent pointers. All inodes must have an extended attribute that points back to |