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author | James Morris <jmorris@namei.org> | 2011-03-08 10:55:06 +1100 |
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committer | James Morris <jmorris@namei.org> | 2011-03-08 10:55:06 +1100 |
commit | 1cc26bada9f6807814806db2f0d78792eecdac71 (patch) | |
tree | 5509b5139db04af6c13db0a580c84116a4a54039 /Documentation/filesystems/porting | |
parent | eae61f3c829439f8f9121b5cd48a14be04df451f (diff) | |
parent | 214d93b02c4fe93638ad268613c9702a81ed9192 (diff) |
Merge branch 'master'; commit 'v2.6.38-rc7' into next
Diffstat (limited to 'Documentation/filesystems/porting')
-rw-r--r-- | Documentation/filesystems/porting | 17 |
1 files changed, 13 insertions, 4 deletions
diff --git a/Documentation/filesystems/porting b/Documentation/filesystems/porting index 07a32b42cf9..dfbcd1b00b0 100644 --- a/Documentation/filesystems/porting +++ b/Documentation/filesystems/porting @@ -365,8 +365,8 @@ must be done in the RCU callback. [recommended] vfs now tries to do path walking in "rcu-walk mode", which avoids atomic operations and scalability hazards on dentries and inodes (see -Documentation/filesystems/path-walk.txt). d_hash and d_compare changes (above) -are examples of the changes required to support this. For more complex +Documentation/filesystems/path-lookup.txt). d_hash and d_compare changes +(above) are examples of the changes required to support this. For more complex filesystem callbacks, the vfs drops out of rcu-walk mode before the fs call, so no changes are required to the filesystem. However, this is costly and loses the benefits of rcu-walk mode. We will begin to add filesystem callbacks that @@ -383,5 +383,14 @@ Documentation/filesystems/vfs.txt for more details. permission and check_acl are inode permission checks that are called on many or all directory inodes on the way down a path walk (to check for -exec permission). These must now be rcu-walk aware (flags & IPERM_RCU). See -Documentation/filesystems/vfs.txt for more details. +exec permission). These must now be rcu-walk aware (flags & IPERM_FLAG_RCU). +See Documentation/filesystems/vfs.txt for more details. + +-- +[mandatory] + In ->fallocate() you must check the mode option passed in. If your +filesystem does not support hole punching (deallocating space in the middle of a +file) you must return -EOPNOTSUPP if FALLOC_FL_PUNCH_HOLE is set in mode. +Currently you can only have FALLOC_FL_PUNCH_HOLE with FALLOC_FL_KEEP_SIZE set, +so the i_size should not change when hole punching, even when puching the end of +a file off. |