diff options
Diffstat (limited to 'Documentation/filesystems')
| -rw-r--r-- | Documentation/filesystems/dax.rst | 6 | ||||
| -rw-r--r-- | Documentation/filesystems/erofs.rst | 2 | ||||
| -rw-r--r-- | Documentation/filesystems/ext4/blocks.rst | 2 | ||||
| -rw-r--r-- | Documentation/filesystems/fscrypt.rst | 25 | ||||
| -rw-r--r-- | Documentation/filesystems/locking.rst | 6 | ||||
| -rw-r--r-- | Documentation/filesystems/porting.rst | 6 | ||||
| -rw-r--r-- | Documentation/filesystems/vfs.rst | 16 |
7 files changed, 47 insertions, 16 deletions
diff --git a/Documentation/filesystems/dax.rst b/Documentation/filesystems/dax.rst index e3b30429d703..c04609d8ee24 100644 --- a/Documentation/filesystems/dax.rst +++ b/Documentation/filesystems/dax.rst @@ -23,11 +23,11 @@ on it as usual. The `DAX` code currently only supports files with a block size equal to your kernel's `PAGE_SIZE`, so you may need to specify a block size when creating the filesystem. -Currently 4 filesystems support `DAX`: ext2, ext4, xfs and virtiofs. +Currently 5 filesystems support `DAX`: ext2, ext4, xfs, virtiofs and erofs. Enabling `DAX` on them is different. -Enabling DAX on ext2 --------------------- +Enabling DAX on ext2 and erofs +------------------------------ When mounting the filesystem, use the ``-o dax`` option on the command line or add 'dax' to the options in ``/etc/fstab``. This works to enable `DAX` on all files diff --git a/Documentation/filesystems/erofs.rst b/Documentation/filesystems/erofs.rst index 7119aa213be7..bef6d3040ce4 100644 --- a/Documentation/filesystems/erofs.rst +++ b/Documentation/filesystems/erofs.rst @@ -40,7 +40,7 @@ Here is the main features of EROFS: Inode metadata size 32 bytes 64 bytes Max file size 4 GB 16 EB (also limited by max. vol size) Max uids/gids 65536 4294967296 - File change time no yes (64 + 32-bit timestamp) + Per-inode timestamp no yes (64 + 32-bit timestamp) Max hardlinks 65536 4294967296 Metadata reserved 4 bytes 14 bytes ===================== ============ ===================================== diff --git a/Documentation/filesystems/ext4/blocks.rst b/Documentation/filesystems/ext4/blocks.rst index bd722ecd92d6..b0f80ea87c90 100644 --- a/Documentation/filesystems/ext4/blocks.rst +++ b/Documentation/filesystems/ext4/blocks.rst @@ -39,7 +39,7 @@ For 32-bit filesystems, limits are as follows: - 4TiB - 8TiB - 16TiB - - 256PiB + - 256TiB * - Blocks Per Block Group - 8,192 - 16,384 diff --git a/Documentation/filesystems/fscrypt.rst b/Documentation/filesystems/fscrypt.rst index 4d5d50dca65c..6ccd5efb25b7 100644 --- a/Documentation/filesystems/fscrypt.rst +++ b/Documentation/filesystems/fscrypt.rst @@ -1047,8 +1047,8 @@ astute users may notice some differences in behavior: may be used to overwrite the source files but isn't guaranteed to be effective on all filesystems and storage devices. -- Direct I/O is not supported on encrypted files. Attempts to use - direct I/O on such files will fall back to buffered I/O. +- Direct I/O is supported on encrypted files only under some + circumstances. For details, see `Direct I/O support`_. - The fallocate operations FALLOC_FL_COLLAPSE_RANGE and FALLOC_FL_INSERT_RANGE are not supported on encrypted files and will @@ -1179,6 +1179,27 @@ Inline encryption doesn't affect the ciphertext or other aspects of the on-disk format, so users may freely switch back and forth between using "inlinecrypt" and not using "inlinecrypt". +Direct I/O support +================== + +For direct I/O on an encrypted file to work, the following conditions +must be met (in addition to the conditions for direct I/O on an +unencrypted file): + +* The file must be using inline encryption. Usually this means that + the filesystem must be mounted with ``-o inlinecrypt`` and inline + encryption hardware must be present. However, a software fallback + is also available. For details, see `Inline encryption support`_. + +* The I/O request must be fully aligned to the filesystem block size. + This means that the file position the I/O is targeting, the lengths + of all I/O segments, and the memory addresses of all I/O buffers + must be multiples of this value. Note that the filesystem block + size may be greater than the logical block size of the block device. + +If either of the above conditions is not met, then direct I/O on the +encrypted file will fall back to buffered I/O. + Implementation details ====================== diff --git a/Documentation/filesystems/locking.rst b/Documentation/filesystems/locking.rst index 72fa12dabd39..2998cec9af4b 100644 --- a/Documentation/filesystems/locking.rst +++ b/Documentation/filesystems/locking.rst @@ -438,13 +438,13 @@ prototypes:: locking rules: ====================== ============= ================= ========= -ops inode->i_lock blocked_lock_lock may block +ops flc_lock blocked_lock_lock may block ====================== ============= ================= ========= -lm_notify: yes yes no +lm_notify: no yes no lm_grant: no no no lm_break: yes no no lm_change yes no no -lm_breaker_owns_lease: no no no +lm_breaker_owns_lease: yes no no ====================== ============= ================= ========= buffer_head diff --git a/Documentation/filesystems/porting.rst b/Documentation/filesystems/porting.rst index bf19fd6b86e7..7c1583dbeb59 100644 --- a/Documentation/filesystems/porting.rst +++ b/Documentation/filesystems/porting.rst @@ -45,6 +45,12 @@ typically between calling iget_locked() and unlocking the inode. At some point that will become mandatory. +**mandatory** + +The foo_inode_info should always be allocated through alloc_inode_sb() rather +than kmem_cache_alloc() or kmalloc() related to set up the inode reclaim context +correctly. + --- **mandatory** diff --git a/Documentation/filesystems/vfs.rst b/Documentation/filesystems/vfs.rst index d16bee420326..4f14edf93941 100644 --- a/Documentation/filesystems/vfs.rst +++ b/Documentation/filesystems/vfs.rst @@ -806,12 +806,16 @@ cache in your filesystem. The following members are defined: object. The pages are consecutive in the page cache and are locked. The implementation should decrement the page refcount after starting I/O on each page. Usually the page will be - unlocked by the I/O completion handler. If the filesystem decides - to stop attempting I/O before reaching the end of the readahead - window, it can simply return. The caller will decrement the page - refcount and unlock the remaining pages for you. Set PageUptodate - if the I/O completes successfully. Setting PageError on any page - will be ignored; simply unlock the page if an I/O error occurs. + unlocked by the I/O completion handler. The set of pages are + divided into some sync pages followed by some async pages, + rac->ra->async_size gives the number of async pages. The + filesystem should attempt to read all sync pages but may decide + to stop once it reaches the async pages. If it does decide to + stop attempting I/O, it can simply return. The caller will + remove the remaining pages from the address space, unlock them + and decrement the page refcount. Set PageUptodate if the I/O + completes successfully. Setting PageError on any page will be + ignored; simply unlock the page if an I/O error occurs. ``readpages`` called by the VM to read pages associated with the address_space |