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Diffstat (limited to 'Documentation/filesystems/porting.rst')
| -rw-r--r-- | Documentation/filesystems/porting.rst | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/Documentation/filesystems/porting.rst b/Documentation/filesystems/porting.rst index ced3a6761329..c549fb2fc3ba 100644 --- a/Documentation/filesystems/porting.rst +++ b/Documentation/filesystems/porting.rst @@ -1064,6 +1064,33 @@ generic_encode_ino32_fh() explicitly. --- +**mandatory** + +If ->rename() update of .. on cross-directory move needs an exclusion with +directory modifications, do *not* lock the subdirectory in question in your +->rename() - it's done by the caller now [that item should've been added in +28eceeda130f "fs: Lock moved directories"]. + +--- + +**mandatory** + +On same-directory ->rename() the (tautological) update of .. is not protected +by any locks; just don't do it if the old parent is the same as the new one. +We really can't lock two subdirectories in same-directory rename - not without +deadlocks. + +--- + +**mandatory** + +lock_rename() and lock_rename_child() may fail in cross-directory case, if +their arguments do not have a common ancestor. In that case ERR_PTR(-EXDEV) +is returned, with no locks taken. In-tree users updated; out-of-tree ones +would need to do so. + +--- + **recommended** Block device freezing and thawing have been moved to holder operations. |