diff options
Diffstat (limited to 'Documentation/filesystems')
| -rw-r--r-- | Documentation/filesystems/porting.rst | 12 | ||||
| -rw-r--r-- | Documentation/filesystems/proc.rst | 5 | ||||
| -rw-r--r-- | Documentation/filesystems/vfs.rst | 4 |
3 files changed, 19 insertions, 2 deletions
diff --git a/Documentation/filesystems/porting.rst b/Documentation/filesystems/porting.rst index d33429294252..3397937ed838 100644 --- a/Documentation/filesystems/porting.rst +++ b/Documentation/filesystems/porting.rst @@ -1286,6 +1286,11 @@ The vm_area_desc provides the minimum required information for a filesystem to initialise state upon memory mapping of a file-backed region, and output parameters for the file system to set this state. +In nearly all cases, this is all that is required for a filesystem. However, if +a filesystem needs to perform an operation such a pre-population of page tables, +then that action can be specified in the vm_area_desc->action field, which can +be configured using the mmap_action_*() helpers. + --- **mandatory** @@ -1322,3 +1327,10 @@ When vfs_mkdir() returns an error, and so both dputs() the original dentry and doesn't provide a replacement, it also unlocks the parent. Consequently the return value from vfs_mkdir() can be passed to end_creating() and the parent will be unlocked precisely when necessary. + +--- + +**mandatory** + +kill_litter_super() is gone; convert to DCACHE_PERSISTENT use (as all +in-tree filesystems have done). diff --git a/Documentation/filesystems/proc.rst b/Documentation/filesystems/proc.rst index 0b86a8022fa1..8256e857e2d7 100644 --- a/Documentation/filesystems/proc.rst +++ b/Documentation/filesystems/proc.rst @@ -553,7 +553,7 @@ otherwise. kernel flags associated with the particular virtual memory area in two letter encoded manner. The codes are the following: - == ======================================= + == ============================================================= rd readable wr writeable ex executable @@ -591,7 +591,8 @@ encoded manner. The codes are the following: sl sealed lf lock on fault pages dp always lazily freeable mapping - == ======================================= + gu maybe contains guard regions (if not set, definitely doesn't) + == ============================================================= Note that there is no guarantee that every flag and associated mnemonic will be present in all further kernel releases. Things get changed, the flags may diff --git a/Documentation/filesystems/vfs.rst b/Documentation/filesystems/vfs.rst index 4f13b01e42eb..670ba66b60e4 100644 --- a/Documentation/filesystems/vfs.rst +++ b/Documentation/filesystems/vfs.rst @@ -1213,6 +1213,10 @@ otherwise noted. file-backed memory mapping, most notably establishing relevant private state and VMA callbacks. + If further action such as pre-population of page tables is required, + this can be specified by the vm_area_desc->action field and related + parameters. + Note that the file operations are implemented by the specific filesystem in which the inode resides. When opening a device node (character or block special) most filesystems will call special |