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authorMiklos Szeredi <mszeredi@suse.cz>2014-10-24 02:14:35 +0400
committerMiklos Szeredi <mszeredi@suse.cz>2014-10-24 02:14:35 +0400
commit4aa7c6346be395bdf776f82bbb2e3e2bc60bdd2b (patch)
treea2135754a04370e7fcf7b867b0f4fbeaa58b3521 /Documentation
parentf114040e3ea6e07372334ade75d1ee0775c355e1 (diff)
downloadlinux-4aa7c6346be395bdf776f82bbb2e3e2bc60bdd2b.tar.xz
vfs: add i_op->dentry_open()
Add a new inode operation i_op->dentry_open(). This is for stacked filesystems that want to return a struct file from a different filesystem. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/filesystems/Locking2
-rw-r--r--Documentation/filesystems/vfs.txt7
2 files changed, 9 insertions, 0 deletions
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index 94d93b1f8b53..b30753cbf431 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -67,6 +67,7 @@ prototypes:
struct file *, unsigned open_flag,
umode_t create_mode, int *opened);
int (*tmpfile) (struct inode *, struct dentry *, umode_t);
+ int (*dentry_open)(struct dentry *, struct file *, const struct cred *);
locking rules:
all may block
@@ -96,6 +97,7 @@ fiemap: no
update_time: no
atomic_open: yes
tmpfile: no
+dentry_open: no
Additionally, ->rmdir(), ->unlink() and ->rename() have ->i_mutex on
victim.
diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
index fceff7c00a3c..20bf204426ca 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -364,6 +364,7 @@ struct inode_operations {
int (*atomic_open)(struct inode *, struct dentry *, struct file *,
unsigned open_flag, umode_t create_mode, int *opened);
int (*tmpfile) (struct inode *, struct dentry *, umode_t);
+ int (*dentry_open)(struct dentry *, struct file *, const struct cred *);
};
Again, all methods are called without any locks being held, unless
@@ -696,6 +697,12 @@ struct address_space_operations {
but instead uses bmap to find out where the blocks in the file
are and uses those addresses directly.
+ dentry_open: *WARNING: probably going away soon, do not use!* This is an
+ alternative to f_op->open(), the difference is that this method may open
+ a file not necessarily originating from the same filesystem as the one
+ i_op->open() was called on. It may be useful for stacking filesystems
+ which want to allow native I/O directly on underlying files.
+
invalidatepage: If a page has PagePrivate set, then invalidatepage
will be called when part or all of the page is to be removed