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| author |   Al Viro <viro@zeniv.linux.org.uk> | 2015-11-17 10:20:54 -0500 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2015-12-08 22:41:54 -0500 |
| commit | 6b2553918d8b4e6de9853fd6315bec7271a2e592 (patch) | |
| tree | 85540dcb0dc0de3d67c68d0aa7b17058f4e96539 /Documentation/filesystems | |
| parent | don't put symlink bodies in pagecache into highmem (diff) | |
| download | linux-dev-6b2553918d8b4e6de9853fd6315bec7271a2e592.tar.xz linux-dev-6b2553918d8b4e6de9853fd6315bec7271a2e592.zip | |
replace ->follow_link() with new method that could stay in RCU mode
new method: ->get_link(); replacement of ->follow_link(). The differences
are:
* inode and dentry are passed separately
* might be called both in RCU and non-RCU mode;
the former is indicated by passing it a NULL dentry.
* when called that way it isn't allowed to block
and should return ERR_PTR(-ECHILD) if it needs to be called
in non-RCU mode.
It's a flagday change - the old method is gone, all in-tree instances
converted. Conversion isn't hard; said that, so far very few instances
do not immediately bail out when called in RCU mode. That'll change
in the next commits.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'Documentation/filesystems')
| -rw-r--r-- | Documentation/filesystems/Locking | 4 | ||||
| -rw-r--r-- | Documentation/filesystems/porting | 6 |
2 files changed, 8 insertions, 2 deletions
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking index 06d443450f21..4fba54b9fcec 100644 --- a/Documentation/filesystems/Locking +++ b/Documentation/filesystems/Locking @@ -50,7 +50,7 @@ prototypes: int (*rename2) (struct inode *, struct dentry *, struct inode *, struct dentry *, unsigned int); int (*readlink) (struct dentry *, char __user *,int); - const char *(*follow_link) (struct dentry *, void **); + const char *(*get_link) (struct dentry *, struct inode *, void **); void (*put_link) (struct inode *, void *); void (*truncate) (struct inode *); int (*permission) (struct inode *, int, unsigned int); @@ -83,7 +83,7 @@ rmdir: yes (both) (see below) rename: yes (all) (see below) rename2: yes (all) (see below) readlink: no -follow_link: no +get_link: no put_link: no setattr: yes permission: no (may not block if called in rcu-walk mode) diff --git a/Documentation/filesystems/porting b/Documentation/filesystems/porting index 3eb7c35c9698..cf92a8c55594 100644 --- a/Documentation/filesystems/porting +++ b/Documentation/filesystems/porting @@ -509,3 +509,9 @@ in your dentry operations instead. any symlink that might use page_follow_link_light/page_put_link() must have inode_nohighmem(inode) called before anything might start playing with its pagecache. +-- +[mandatory] + ->follow_link() is replaced with ->get_link(); same API, except that + * ->get_link() gets inode as a separate argument + * ->get_link() may be called in RCU mode - in that case NULL + dentry is passed |