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authorLinus Torvalds <torvalds@linux-foundation.org>2013-02-26 20:16:07 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2013-02-26 20:16:07 -0800
commitd895cb1af15c04c522a25c79cc429076987c089b (patch)
tree895dc9157e28f603d937a58be664e4e440d5530c /Documentation/filesystems/vfs.txt
parent9626357371b519f2b955fef399647181034a77fe (diff)
parentd3d009cb965eae7e002ea5badf603ea8f4c34915 (diff)
downloadlinaro-lsk-d895cb1af15c04c522a25c79cc429076987c089b.tar.gz
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs pile (part one) from Al Viro: "Assorted stuff - cleaning namei.c up a bit, fixing ->d_name/->d_parent locking violations, etc. The most visible changes here are death of FS_REVAL_DOT (replaced with "has ->d_weak_revalidate()") and a new helper getting from struct file to inode. Some bits of preparation to xattr method interface changes. Misc patches by various people sent this cycle *and* ocfs2 fixes from several cycles ago that should've been upstream right then. PS: the next vfs pile will be xattr stuff." * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (46 commits) saner proc_get_inode() calling conventions proc: avoid extra pde_put() in proc_fill_super() fs: change return values from -EACCES to -EPERM fs/exec.c: make bprm_mm_init() static ocfs2/dlm: use GFP_ATOMIC inside a spin_lock ocfs2: fix possible use-after-free with AIO ocfs2: Fix oops in ocfs2_fast_symlink_readpage() code path get_empty_filp()/alloc_file() leave both ->f_pos and ->f_version zero target: writev() on single-element vector is pointless export kernel_write(), convert open-coded instances fs: encode_fh: return FILEID_INVALID if invalid fid_type kill f_vfsmnt vfs: kill FS_REVAL_DOT by adding a d_weak_revalidate dentry op nfsd: handle vfs_getattr errors in acl protocol switch vfs_getattr() to struct path default SET_PERSONALITY() in linux/elf.h ceph: prepopulate inodes only when request is aborted d_hash_and_lookup(): export, switch open-coded instances 9p: switch v9fs_set_create_acl() to inode+fid, do it before d_instantiate() 9p: split dropping the acls from v9fs_set_create_acl() ...
Diffstat (limited to 'Documentation/filesystems/vfs.txt')
-rw-r--r--Documentation/filesystems/vfs.txt24
1 files changed, 22 insertions, 2 deletions
diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
index e3869098163..bc4b06b3160 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -900,6 +900,7 @@ defined:
struct dentry_operations {
int (*d_revalidate)(struct dentry *, unsigned int);
+ int (*d_weak_revalidate)(struct dentry *, unsigned int);
int (*d_hash)(const struct dentry *, const struct inode *,
struct qstr *);
int (*d_compare)(const struct dentry *, const struct inode *,
@@ -915,8 +916,13 @@ struct dentry_operations {
d_revalidate: called when the VFS needs to revalidate a dentry. This
is called whenever a name look-up finds a dentry in the
- dcache. Most filesystems leave this as NULL, because all their
- dentries in the dcache are valid
+ dcache. Most local filesystems leave this as NULL, because all their
+ dentries in the dcache are valid. Network filesystems are different
+ since things can change on the server without the client necessarily
+ being aware of it.
+
+ This function should return a positive value if the dentry is still
+ valid, and zero or a negative error code if it isn't.
d_revalidate may be called in rcu-walk mode (flags & LOOKUP_RCU).
If in rcu-walk mode, the filesystem must revalidate the dentry without
@@ -927,6 +933,20 @@ struct dentry_operations {
If a situation is encountered that rcu-walk cannot handle, return
-ECHILD and it will be called again in ref-walk mode.
+ d_weak_revalidate: called when the VFS needs to revalidate a "jumped" dentry.
+ This is called when a path-walk ends at dentry that was not acquired by
+ doing a lookup in the parent directory. This includes "/", "." and "..",
+ as well as procfs-style symlinks and mountpoint traversal.
+
+ In this case, we are less concerned with whether the dentry is still
+ fully correct, but rather that the inode is still valid. As with
+ d_revalidate, most local filesystems will set this to NULL since their
+ dcache entries are always valid.
+
+ This function has the same return code semantics as d_revalidate.
+
+ d_weak_revalidate is only called after leaving rcu-walk mode.
+
d_hash: called when the VFS adds a dentry to the hash table. The first
dentry passed to d_hash is the parent directory that the name is
to be hashed into. The inode is the dentry's inode.