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Diffstat (limited to 'Documentation/filesystems/porting.rst')
| -rw-r--r-- | Documentation/filesystems/porting.rst | 48 |
1 files changed, 47 insertions, 1 deletions
diff --git a/Documentation/filesystems/porting.rst b/Documentation/filesystems/porting.rst index 1639e78e3146..767b2927c762 100644 --- a/Documentation/filesystems/porting.rst +++ b/Documentation/filesystems/porting.rst @@ -1144,7 +1144,7 @@ and it *must* be opened exclusive. --- -** mandatory** +**mandatory** ->d_revalidate() gets two extra arguments - inode of parent directory and name our dentry is expected to have. Both are stable (dir is pinned in @@ -1157,3 +1157,49 @@ in normal case it points into the pathname being looked up. NOTE: if you need something like full path from the root of filesystem, you are still on your own - this assists with simple cases, but it's not magic. + +--- + +**recommended** + +kern_path_locked() and user_path_locked() no longer return a negative +dentry so this doesn't need to be checked. If the name cannot be found, +ERR_PTR(-ENOENT) is returned. + +--- + +**recommended** + +lookup_one_qstr_excl() is changed to return errors in more cases, so +these conditions don't require explicit checks: + + - if LOOKUP_CREATE is NOT given, then the dentry won't be negative, + ERR_PTR(-ENOENT) is returned instead + - if LOOKUP_EXCL IS given, then the dentry won't be positive, + ERR_PTR(-EEXIST) is rreturned instread + +LOOKUP_EXCL now means "target must not exist". It can be combined with +LOOK_CREATE or LOOKUP_RENAME_TARGET. + +--- + +**mandatory** +invalidate_inodes() is gone use evict_inodes() instead. + +--- + +**mandatory** + +->mkdir() now returns a dentry. If the created inode is found to +already be in cache and have a dentry (often IS_ROOT()), it will need to +be spliced into the given name in place of the given dentry. That dentry +now needs to be returned. If the original dentry is used, NULL should +be returned. Any error should be returned with ERR_PTR(). + +In general, filesystems which use d_instantiate_new() to install the new +inode can safely return NULL. Filesystems which may not have an I_NEW inode +should use d_drop();d_splice_alias() and return the result of the latter. + +If a positive dentry cannot be returned for some reason, in-kernel +clients such as cachefiles, nfsd, smb/server may not perform ideally but +will fail-safe. |