diff options
Diffstat (limited to 'Documentation/filesystems')
| -rw-r--r-- | Documentation/filesystems/afs.rst | 8 | ||||
| -rw-r--r-- | Documentation/filesystems/dax.txt | 17 | ||||
| -rw-r--r-- | Documentation/filesystems/f2fs.rst | 19 | ||||
| -rw-r--r-- | Documentation/filesystems/fsverity.rst | 76 | ||||
| -rw-r--r-- | Documentation/filesystems/index.rst | 1 | ||||
| -rw-r--r-- | Documentation/filesystems/locking.rst | 7 | ||||
| -rw-r--r-- | Documentation/filesystems/overlayfs.rst | 8 | ||||
| -rw-r--r-- | Documentation/filesystems/porting.rst | 18 | ||||
| -rw-r--r-- | Documentation/filesystems/proc.rst | 9 | ||||
| -rw-r--r-- | Documentation/filesystems/seq_file.rst | 6 | ||||
| -rw-r--r-- | Documentation/filesystems/vfs.rst | 26 |
11 files changed, 160 insertions, 35 deletions
diff --git a/Documentation/filesystems/afs.rst b/Documentation/filesystems/afs.rst index 0abb155ac666..ca062a7f8ee2 100644 --- a/Documentation/filesystems/afs.rst +++ b/Documentation/filesystems/afs.rst @@ -109,7 +109,7 @@ Mountpoints AFS has a concept of mountpoints. In AFS terms, these are specially formatted symbolic links (of the same form as the "device name" passed to mount). kAFS presents these to the user as directories that have a follow-link capability -(ie: symbolic link semantics). If anyone attempts to access them, they will +(i.e.: symbolic link semantics). If anyone attempts to access them, they will automatically cause the target volume to be mounted (if possible) on that site. Automatically mounted filesystems will be automatically unmounted approximately @@ -144,7 +144,7 @@ looks up a cell of the same name, for example:: Proc Filesystem =============== -The AFS modules creates a "/proc/fs/afs/" directory and populates it: +The AFS module creates a "/proc/fs/afs/" directory and populates it: (*) A "cells" file that lists cells currently known to the afs module and their usage counts:: @@ -201,7 +201,7 @@ And then run as:: ./klog Assuming it's successful, this adds a key of type RxRPC, named for the service -and cell, eg: "afs@<cellname>". This can be viewed with the keyctl program or +and cell, e.g.: "afs@<cellname>". This can be viewed with the keyctl program or by cat'ing /proc/keys:: [root@andromeda ~]# keyctl show @@ -211,7 +211,7 @@ by cat'ing /proc/keys:: 111416553 --als--v 0 0 \_ rxrpc: afs@CAMBRIDGE.REDHAT.COM Currently the username, realm, password and proposed ticket lifetime are -compiled in to the program. +compiled into the program. It is not required to acquire a key before using AFS facilities, but if one is not acquired then all operations will be governed by the anonymous user parts diff --git a/Documentation/filesystems/dax.txt b/Documentation/filesystems/dax.txt index 8fdb78f3c6c9..e03c20564f3a 100644 --- a/Documentation/filesystems/dax.txt +++ b/Documentation/filesystems/dax.txt @@ -83,20 +83,9 @@ Summary directories. This has runtime constraints and limitations that are described in 6) below. - 6. When changing the S_DAX policy via toggling the persistent FS_XFLAG_DAX flag, - the change in behaviour for existing regular files may not occur - immediately. If the change must take effect immediately, the administrator - needs to: - - a) stop the application so there are no active references to the data set - the policy change will affect - - b) evict the data set from kernel caches so it will be re-instantiated when - the application is restarted. This can be achieved by: - - i. drop-caches - ii. a filesystem unmount and mount cycle - iii. a system reboot + 6. When changing the S_DAX policy via toggling the persistent FS_XFLAG_DAX + flag, the change to existing regular files won't take effect until the + files are closed by all processes. Details diff --git a/Documentation/filesystems/f2fs.rst b/Documentation/filesystems/f2fs.rst index dae15c96e659..35ed01a5fbc9 100644 --- a/Documentation/filesystems/f2fs.rst +++ b/Documentation/filesystems/f2fs.rst @@ -179,7 +179,6 @@ fault_type=%d Support configuring fault injection type, should be FAULT_KVMALLOC 0x000000002 FAULT_PAGE_ALLOC 0x000000004 FAULT_PAGE_GET 0x000000008 - FAULT_ALLOC_BIO 0x000000010 FAULT_ALLOC_NID 0x000000020 FAULT_ORPHAN 0x000000040 FAULT_BLOCK 0x000000080 @@ -247,8 +246,24 @@ checkpoint=%s[:%u[%]] Set to "disable" to turn off checkpointing. Set to "enabl hide up to all remaining free space. The actual space that would be unusable can be viewed at /sys/fs/f2fs/<disk>/unusable This space is reclaimed once checkpoint=enable. +checkpoint_merge When checkpoint is enabled, this can be used to create a kernel + daemon and make it to merge concurrent checkpoint requests as + much as possible to eliminate redundant checkpoint issues. Plus, + we can eliminate the sluggish issue caused by slow checkpoint + operation when the checkpoint is done in a process context in + a cgroup having low i/o budget and cpu shares. To make this + do better, we set the default i/o priority of the kernel daemon + to "3", to give one higher priority than other kernel threads. + This is the same way to give a I/O priority to the jbd2 + journaling thread of ext4 filesystem. +nocheckpoint_merge Disable checkpoint merge feature. compress_algorithm=%s Control compress algorithm, currently f2fs supports "lzo", "lz4", "zstd" and "lzo-rle" algorithm. +compress_algorithm=%s:%d Control compress algorithm and its compress level, now, only + "lz4" and "zstd" support compress level config. + algorithm level range + lz4 3 - 16 + zstd 1 - 22 compress_log_size=%u Support configuring compress cluster size, the size will be 4KB * (1 << %u), 16KB is minimum size, also it's default size. @@ -831,7 +846,7 @@ This is the default option. f2fs does automatic compression in the writeback of compression enabled files. 2) compress_mode=user -This disables the automaic compression and gives the user discretion of choosing the +This disables the automatic compression and gives the user discretion of choosing the target file and the timing. The user can do manual compression/decompression on the compression enabled files using F2FS_IOC_DECOMPRESS_FILE and F2FS_IOC_COMPRESS_FILE ioctls like the below. diff --git a/Documentation/filesystems/fsverity.rst b/Documentation/filesystems/fsverity.rst index e0204a23e997..1d831e3cbcb3 100644 --- a/Documentation/filesystems/fsverity.rst +++ b/Documentation/filesystems/fsverity.rst @@ -217,6 +217,82 @@ FS_IOC_MEASURE_VERITY can fail with the following errors: - ``EOVERFLOW``: the digest is longer than the specified ``digest_size`` bytes. Try providing a larger buffer. +FS_IOC_READ_VERITY_METADATA +--------------------------- + +The FS_IOC_READ_VERITY_METADATA ioctl reads verity metadata from a +verity file. This ioctl is available since Linux v5.12. + +This ioctl allows writing a server program that takes a verity file +and serves it to a client program, such that the client can do its own +fs-verity compatible verification of the file. This only makes sense +if the client doesn't trust the server and if the server needs to +provide the storage for the client. + +This is a fairly specialized use case, and most fs-verity users won't +need this ioctl. + +This ioctl takes in a pointer to the following structure:: + + #define FS_VERITY_METADATA_TYPE_MERKLE_TREE 1 + #define FS_VERITY_METADATA_TYPE_DESCRIPTOR 2 + #define FS_VERITY_METADATA_TYPE_SIGNATURE 3 + + struct fsverity_read_metadata_arg { + __u64 metadata_type; + __u64 offset; + __u64 length; + __u64 buf_ptr; + __u64 __reserved; + }; + +``metadata_type`` specifies the type of metadata to read: + +- ``FS_VERITY_METADATA_TYPE_MERKLE_TREE`` reads the blocks of the + Merkle tree. The blocks are returned in order from the root level + to the leaf level. Within each level, the blocks are returned in + the same order that their hashes are themselves hashed. + See `Merkle tree`_ for more information. + +- ``FS_VERITY_METADATA_TYPE_DESCRIPTOR`` reads the fs-verity + descriptor. See `fs-verity descriptor`_. + +- ``FS_VERITY_METADATA_TYPE_SIGNATURE`` reads the signature which was + passed to FS_IOC_ENABLE_VERITY, if any. See `Built-in signature + verification`_. + +The semantics are similar to those of ``pread()``. ``offset`` +specifies the offset in bytes into the metadata item to read from, and +``length`` specifies the maximum number of bytes to read from the +metadata item. ``buf_ptr`` is the pointer to the buffer to read into, +cast to a 64-bit integer. ``__reserved`` must be 0. On success, the +number of bytes read is returned. 0 is returned at the end of the +metadata item. The returned length may be less than ``length``, for +example if the ioctl is interrupted. + +The metadata returned by FS_IOC_READ_VERITY_METADATA isn't guaranteed +to be authenticated against the file digest that would be returned by +`FS_IOC_MEASURE_VERITY`_, as the metadata is expected to be used to +implement fs-verity compatible verification anyway (though absent a +malicious disk, the metadata will indeed match). E.g. to implement +this ioctl, the filesystem is allowed to just read the Merkle tree +blocks from disk without actually verifying the path to the root node. + +FS_IOC_READ_VERITY_METADATA can fail with the following errors: + +- ``EFAULT``: the caller provided inaccessible memory +- ``EINTR``: the ioctl was interrupted before any data was read +- ``EINVAL``: reserved fields were set, or ``offset + length`` + overflowed +- ``ENODATA``: the file is not a verity file, or + FS_VERITY_METADATA_TYPE_SIGNATURE was requested but the file doesn't + have a built-in signature +- ``ENOTTY``: this type of filesystem does not implement fs-verity, or + this ioctl is not yet implemented on it +- ``EOPNOTSUPP``: the kernel was not configured with fs-verity + support, or the filesystem superblock has not had the 'verity' + feature enabled on it. (See `Filesystem support`_.) + FS_IOC_GETFLAGS --------------- diff --git a/Documentation/filesystems/index.rst b/Documentation/filesystems/index.rst index 7be9b46d85d9..1f76b1cb3348 100644 --- a/Documentation/filesystems/index.rst +++ b/Documentation/filesystems/index.rst @@ -83,6 +83,7 @@ Documentation for filesystem implementations. erofs ext2 ext3 + ext4/index f2fs gfs2 gfs2-uevents diff --git a/Documentation/filesystems/locking.rst b/Documentation/filesystems/locking.rst index c0f2c7586531..b7dcc86c92a4 100644 --- a/Documentation/filesystems/locking.rst +++ b/Documentation/filesystems/locking.rst @@ -126,9 +126,10 @@ prototypes:: int (*get)(const struct xattr_handler *handler, struct dentry *dentry, struct inode *inode, const char *name, void *buffer, size_t size); - int (*set)(const struct xattr_handler *handler, struct dentry *dentry, - struct inode *inode, const char *name, const void *buffer, - size_t size, int flags); + int (*set)(const struct xattr_handler *handler, + struct user_namespace *mnt_userns, + struct dentry *dentry, struct inode *inode, const char *name, + const void *buffer, size_t size, int flags); locking rules: all may block diff --git a/Documentation/filesystems/overlayfs.rst b/Documentation/filesystems/overlayfs.rst index 587a93973929..78240e29b0bb 100644 --- a/Documentation/filesystems/overlayfs.rst +++ b/Documentation/filesystems/overlayfs.rst @@ -586,6 +586,14 @@ without significant effort. The advantage of mounting with the "volatile" option is that all forms of sync calls to the upper filesystem are omitted. +In order to avoid a giving a false sense of safety, the syncfs (and fsync) +semantics of volatile mounts are slightly different than that of the rest of +VFS. If any writeback error occurs on the upperdir's filesystem after a +volatile mount takes place, all sync functions will return an error. Once this +condition is reached, the filesystem will not recover, and every subsequent sync +call will return an error, even if the upperdir has not experience a new error +since the last sync call. + When overlay is mounted with "volatile" option, the directory "$workdir/work/incompat/volatile" is created. During next mount, overlay checks for this directory and refuses to mount if present. This is a strong diff --git a/Documentation/filesystems/porting.rst b/Documentation/filesystems/porting.rst index 6a6d3e673b48..0302035781be 100644 --- a/Documentation/filesystems/porting.rst +++ b/Documentation/filesystems/porting.rst @@ -717,6 +717,8 @@ be removed. Switch while you still can; the old one won't stay. **mandatory** ->setxattr() and xattr_handler.set() get dentry and inode passed separately. +The xattr_handler.set() gets passed the user namespace of the mount the inode +is seen from so filesystems can idmap the i_uid and i_gid accordingly. dentry might be yet to be attached to inode, so do _not_ use its ->d_inode in the instances. Rationale: !@#!@# security_d_instantiate() needs to be called before we attach dentry to inode and !@#!@##!@$!$#!@#$!@$!@$ smack @@ -870,5 +872,21 @@ its result is kern_unmount() or kern_unmount_array(). **mandatory** +zero-length bvec segments are disallowed, they must be filtered out before +passed on to an iterator. + +--- + +**mandatory** + +For bvec based itererators bio_iov_iter_get_pages() now doesn't copy bvecs but +uses the one provided. Anyone issuing kiocb-I/O should ensure that the bvec and +page references stay until I/O has completed, i.e. until ->ki_complete() has +been called or returned with non -EIOCBQUEUED code. + +--- + +**mandatory** + mnt_want_write_file() can now only be paired with mnt_drop_write_file(), whereas previously it could be paired with mnt_drop_write() as well. diff --git a/Documentation/filesystems/proc.rst b/Documentation/filesystems/proc.rst index 2fa69f710e2a..48fbfc336ebf 100644 --- a/Documentation/filesystems/proc.rst +++ b/Documentation/filesystems/proc.rst @@ -687,7 +687,14 @@ files are there, and which are missing. kcore Kernel core image (can be ELF or A.OUT(deprecated in 2.4)) kmsg Kernel messages ksyms Kernel symbol table - loadavg Load average of last 1, 5 & 15 minutes + loadavg Load average of last 1, 5 & 15 minutes; + number of processes currently runnable (running or on ready queue); + total number of processes in system; + last pid created. + All fields are separated by one space except "number of + processes currently runnable" and "total number of processes + in system", which are separated by a slash ('/'). Example: + 0.61 0.61 0.55 3/828 22084 locks Kernel locks meminfo Memory info misc Miscellaneous diff --git a/Documentation/filesystems/seq_file.rst b/Documentation/filesystems/seq_file.rst index 56856481dc8d..a6726082a7c2 100644 --- a/Documentation/filesystems/seq_file.rst +++ b/Documentation/filesystems/seq_file.rst @@ -217,6 +217,12 @@ between the calls to start() and stop(), so holding a lock during that time is a reasonable thing to do. The seq_file code will also avoid taking any other locks while the iterator is active. +The iterater value returned by start() or next() is guaranteed to be +passed to a subsequent next() or stop() call. This allows resources +such as locks that were taken to be reliably released. There is *no* +guarantee that the iterator will be passed to show(), though in practice +it often will be. + Formatted output ================ diff --git a/Documentation/filesystems/vfs.rst b/Documentation/filesystems/vfs.rst index ca52c82e5bb5..2049bbf5e388 100644 --- a/Documentation/filesystems/vfs.rst +++ b/Documentation/filesystems/vfs.rst @@ -112,7 +112,7 @@ members are defined: .. code-block:: c - struct file_system_operations { + struct file_system_type { const char *name; int fs_flags; struct dentry *(*mount) (struct file_system_type *, int, @@ -270,7 +270,10 @@ or bottom half). ->alloc_inode. ``dirty_inode`` - this method is called by the VFS to mark an inode dirty. + this method is called by the VFS when an inode is marked dirty. + This is specifically for the inode itself being marked dirty, + not its data. If the update needs to be persisted by fdatasync(), + then I_DIRTY_DATASYNC will be set in the flags argument. ``write_inode`` this method is called when the VFS needs to write an inode to @@ -415,28 +418,29 @@ As of kernel 2.6.22, the following members are defined: .. code-block:: c struct inode_operations { - int (*create) (struct inode *,struct dentry *, umode_t, bool); + int (*create) (struct user_namespace *, struct inode *,struct dentry *, umode_t, bool); struct dentry * (*lookup) (struct inode *,struct dentry *, unsigned int); int (*link) (struct dentry *,struct inode *,struct dentry *); int (*unlink) (struct inode *,struct dentry *); - int (*symlink) (struct inode *,struct dentry *,const char *); - int (*mkdir) (struct inode *,struct dentry *,umode_t); + int (*symlink) (struct user_namespace *, struct inode *,struct dentry *,const char *); + int (*mkdir) (struct user_namespace *, struct inode *,struct dentry *,umode_t); int (*rmdir) (struct inode *,struct dentry *); - int (*mknod) (struct inode *,struct dentry *,umode_t,dev_t); - int (*rename) (struct inode *, struct dentry *, + int (*mknod) (struct user_namespace *, struct inode *,struct dentry *,umode_t,dev_t); + int (*rename) (struct user_namespace *, struct inode *, struct dentry *, struct inode *, struct dentry *, unsigned int); int (*readlink) (struct dentry *, char __user *,int); const char *(*get_link) (struct dentry *, struct inode *, struct delayed_call *); - int (*permission) (struct inode *, int); + int (*permission) (struct user_namespace *, struct inode *, int); int (*get_acl)(struct inode *, int); - int (*setattr) (struct dentry *, struct iattr *); - int (*getattr) (const struct path *, struct kstat *, u32, unsigned int); + int (*setattr) (struct user_namespace *, struct dentry *, struct iattr *); + int (*getattr) (struct user_namespace *, const struct path *, struct kstat *, u32, unsigned int); ssize_t (*listxattr) (struct dentry *, char *, size_t); void (*update_time)(struct inode *, struct timespec *, int); int (*atomic_open)(struct inode *, struct dentry *, struct file *, unsigned open_flag, umode_t create_mode); - int (*tmpfile) (struct inode *, struct dentry *, umode_t); + int (*tmpfile) (struct user_namespace *, struct inode *, struct dentry *, umode_t); + int (*set_acl)(struct user_namespace *, struct inode *, struct posix_acl *, int); }; Again, all methods are called without any locks being held, unless |