diff options
Diffstat (limited to 'Documentation/filesystems')
15 files changed, 167 insertions, 74 deletions
diff --git a/Documentation/filesystems/erofs.rst b/Documentation/filesystems/erofs.rst index 57c6ae23b3fc..cc4626d6ee4f 100644 --- a/Documentation/filesystems/erofs.rst +++ b/Documentation/filesystems/erofs.rst @@ -91,6 +91,10 @@ compatibility checking tool (fsck.erofs), and a debugging tool (dump.erofs): - git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs-utils.git +For more information, please also refer to the documentation site: + +- https://erofs.docs.kernel.org + Bugs and patches are welcome, please kindly help us and send to the following linux-erofs mailing list: diff --git a/Documentation/filesystems/fscrypt.rst b/Documentation/filesystems/fscrypt.rst index 1b84f818e574..e86b886b64d0 100644 --- a/Documentation/filesystems/fscrypt.rst +++ b/Documentation/filesystems/fscrypt.rst @@ -31,15 +31,15 @@ However, except for filenames, fscrypt does not encrypt filesystem metadata. Unlike eCryptfs, which is a stacked filesystem, fscrypt is integrated -directly into supported filesystems --- currently ext4, F2FS, and -UBIFS. This allows encrypted files to be read and written without -caching both the decrypted and encrypted pages in the pagecache, -thereby nearly halving the memory used and bringing it in line with -unencrypted files. Similarly, half as many dentries and inodes are -needed. eCryptfs also limits encrypted filenames to 143 bytes, -causing application compatibility issues; fscrypt allows the full 255 -bytes (NAME_MAX). Finally, unlike eCryptfs, the fscrypt API can be -used by unprivileged users, with no need to mount anything. +directly into supported filesystems --- currently ext4, F2FS, UBIFS, +and CephFS. This allows encrypted files to be read and written +without caching both the decrypted and encrypted pages in the +pagecache, thereby nearly halving the memory used and bringing it in +line with unencrypted files. Similarly, half as many dentries and +inodes are needed. eCryptfs also limits encrypted filenames to 143 +bytes, causing application compatibility issues; fscrypt allows the +full 255 bytes (NAME_MAX). Finally, unlike eCryptfs, the fscrypt API +can be used by unprivileged users, with no need to mount anything. fscrypt does not support encrypting files in-place. Instead, it supports marking an empty directory as encrypted. Then, after @@ -1382,7 +1382,8 @@ directory.) These structs are defined as follows:: u8 contents_encryption_mode; u8 filenames_encryption_mode; u8 flags; - u8 __reserved[4]; + u8 log2_data_unit_size; + u8 __reserved[3]; u8 master_key_identifier[FSCRYPT_KEY_IDENTIFIER_SIZE]; u8 nonce[FSCRYPT_FILE_NONCE_SIZE]; }; diff --git a/Documentation/filesystems/fuse-io.rst b/Documentation/filesystems/fuse-io.rst index 255a368fe534..6464de4266ad 100644 --- a/Documentation/filesystems/fuse-io.rst +++ b/Documentation/filesystems/fuse-io.rst @@ -15,7 +15,8 @@ The direct-io mode can be selected with the FOPEN_DIRECT_IO flag in the FUSE_OPEN reply. In direct-io mode the page cache is completely bypassed for reads and writes. -No read-ahead takes place. Shared mmap is disabled. +No read-ahead takes place. Shared mmap is disabled by default. To allow shared +mmap, the FUSE_DIRECT_IO_ALLOW_MMAP flag may be enabled in the FUSE_INIT reply. In cached mode reads may be satisfied from the page cache, and data may be read-ahead by the kernel to fill the cache. The cache is always kept consistent diff --git a/Documentation/filesystems/index.rst b/Documentation/filesystems/index.rst index 09cade7eaefc..e18bc5ae3b35 100644 --- a/Documentation/filesystems/index.rst +++ b/Documentation/filesystems/index.rst @@ -121,8 +121,5 @@ Documentation for filesystem implementations. udf virtiofs vfat - xfs-delayed-logging-design - xfs-maintainer-entry-profile - xfs-self-describing-metadata - xfs-online-fsck-design + xfs/index zonefs diff --git a/Documentation/filesystems/locking.rst b/Documentation/filesystems/locking.rst index 7be2900806c8..421daf837940 100644 --- a/Documentation/filesystems/locking.rst +++ b/Documentation/filesystems/locking.rst @@ -261,7 +261,7 @@ prototypes:: struct folio *src, enum migrate_mode); int (*launder_folio)(struct folio *); bool (*is_partially_uptodate)(struct folio *, size_t from, size_t count); - int (*error_remove_page)(struct address_space *, struct page *); + int (*error_remove_folio)(struct address_space *, struct folio *); int (*swap_activate)(struct swap_info_struct *sis, struct file *f, sector_t *span) int (*swap_deactivate)(struct file *); int (*swap_rw)(struct kiocb *iocb, struct iov_iter *iter); @@ -287,7 +287,7 @@ direct_IO: migrate_folio: yes (both) launder_folio: yes is_partially_uptodate: yes -error_remove_page: yes +error_remove_folio: yes swap_activate: no swap_deactivate: no swap_rw: yes, unlocks diff --git a/Documentation/filesystems/overlayfs.rst b/Documentation/filesystems/overlayfs.rst index 0407f361f32a..1c244866041a 100644 --- a/Documentation/filesystems/overlayfs.rst +++ b/Documentation/filesystems/overlayfs.rst @@ -39,7 +39,7 @@ objects in the original filesystem. On 64bit systems, even if all overlay layers are not on the same underlying filesystem, the same compliant behavior could be achieved with the "xino" feature. The "xino" feature composes a unique object -identifier from the real object st_ino and an underlying fsid index. +identifier from the real object st_ino and an underlying fsid number. The "xino" feature uses the high inode number bits for fsid, because the underlying filesystems rarely use the high inode number bits. In case the underlying inode number does overflow into the high xino bits, overlay @@ -118,7 +118,7 @@ Where both upper and lower objects are directories, a merged directory is formed. At mount time, the two directories given as mount options "lowerdir" and -"upperdir" are combined into a merged directory: +"upperdir" are combined into a merged directory:: mount -t overlay overlay -olowerdir=/lower,upperdir=/upper,\ workdir=/work /merged @@ -172,12 +172,12 @@ directory is being read. This is unlikely to be noticed by many programs. seek offsets are assigned sequentially when the directories are read. -Thus if +Thus if: - - read part of a directory - - remember an offset, and close the directory - - re-open the directory some time later - - seek to the remembered offset + - read part of a directory + - remember an offset, and close the directory + - re-open the directory some time later + - seek to the remembered offset there may be little correlation between the old and new locations in the list of filenames, particularly if anything has changed in the @@ -290,9 +290,9 @@ Permission checking in the overlay filesystem follows these principles: 2) task creating the overlay mount MUST NOT gain additional privileges 3) non-mounting task MAY gain additional privileges through the overlay, - compared to direct access on underlying lower or upper filesystems + compared to direct access on underlying lower or upper filesystems -This is achieved by performing two permission checks on each access +This is achieved by performing two permission checks on each access: a) check if current task is allowed access based on local DAC (owner, group, mode and posix acl), as well as MAC checks @@ -311,11 +311,11 @@ to create setups where the consistency rule (1) does not hold; normally, however, the mounting task will have sufficient privileges to perform all operations. -Another way to demonstrate this model is drawing parallels between +Another way to demonstrate this model is drawing parallels between:: mount -t overlay overlay -olowerdir=/lower,upperdir=/upper,... /merged -and +and:: cp -a /lower /upper mount --bind /upper /merged @@ -328,7 +328,7 @@ Multiple lower layers --------------------- Multiple lower layers can now be given using the colon (":") as a -separator character between the directory names. For example: +separator character between the directory names. For example:: mount -t overlay overlay -olowerdir=/lower1:/lower2:/lower3 /merged @@ -340,13 +340,13 @@ rightmost one and going left. In the above example lower1 will be the top, lower2 the middle and lower3 the bottom layer. Note: directory names containing colons can be provided as lower layer by -escaping the colons with a single backslash. For example: +escaping the colons with a single backslash. For example:: mount -t overlay overlay -olowerdir=/a\:lower\:\:dir /merged Since kernel version v6.8, directory names containing colons can also be configured as lower layer using the "lowerdir+" mount options and the -fsconfig syscall from new mount api. For example: +fsconfig syscall from new mount api. For example:: fsconfig(fs_fd, FSCONFIG_SET_STRING, "lowerdir+", "/a:lower::dir", 0); @@ -356,7 +356,7 @@ as an octal characters (\072) when displayed in /proc/self/mountinfo. Metadata only copy up --------------------- -When metadata only copy up feature is enabled, overlayfs will only copy +When the "metacopy" feature is enabled, overlayfs will only copy up metadata (as opposed to whole file), when a metadata specific operation like chown/chmod is performed. Full file will be copied up later when file is opened for WRITE operation. @@ -405,7 +405,7 @@ A normal lower layer is not allowed to be below a data-only layer, so single colon separators are not allowed to the right of double colon ("::") separators. -For example: +For example:: mount -t overlay overlay -olowerdir=/l1:/l2:/l3::/do1::/do2 /merged @@ -419,7 +419,7 @@ to the absolute path of the "lower data" file in the "data-only" lower layer. Since kernel version v6.8, "data-only" lower layers can also be added using the "datadir+" mount options and the fsconfig syscall from new mount api. -For example: +For example:: fsconfig(fs_fd, FSCONFIG_SET_STRING, "lowerdir+", "/l1", 0); fsconfig(fs_fd, FSCONFIG_SET_STRING, "lowerdir+", "/l2", 0); @@ -429,7 +429,7 @@ For example: fs-verity support ----------------------- +----------------- During metadata copy up of a lower file, if the source file has fs-verity enabled and overlay verity support is enabled, then the @@ -492,27 +492,27 @@ though it will not result in a crash or deadlock. Mounting an overlay using an upper layer path, where the upper layer path was previously used by another mounted overlay in combination with a -different lower layer path, is allowed, unless the "inodes index" feature -or "metadata only copy up" feature is enabled. +different lower layer path, is allowed, unless the "index" or "metacopy" +features are enabled. -With the "inodes index" feature, on the first time mount, an NFS file +With the "index" feature, on the first time mount, an NFS file handle of the lower layer root directory, along with the UUID of the lower filesystem, are encoded and stored in the "trusted.overlay.origin" extended attribute on the upper layer root directory. On subsequent mount attempts, the lower root directory file handle and lower filesystem UUID are compared to the stored origin in upper root directory. On failure to verify the lower root origin, mount will fail with ESTALE. An overlayfs mount with -"inodes index" enabled will fail with EOPNOTSUPP if the lower filesystem +"index" enabled will fail with EOPNOTSUPP if the lower filesystem does not support NFS export, lower filesystem does not have a valid UUID or if the upper filesystem does not support extended attributes. -For "metadata only copy up" feature there is no verification mechanism at +For the "metacopy" feature, there is no verification mechanism at mount time. So if same upper is mounted with different set of lower, mount probably will succeed but expect the unexpected later on. So don't do it. It is quite a common practice to copy overlay layers to a different directory tree on the same or different underlying filesystem, and even -to a different machine. With the "inodes index" feature, trying to mount +to a different machine. With the "index" feature, trying to mount the copied layers will fail the verification of the lower root file handle. Nesting overlayfs mounts @@ -547,20 +547,21 @@ filesystem. This is the list of cases that overlayfs doesn't currently handle: -a) POSIX mandates updating st_atime for reads. This is currently not -done in the case when the file resides on a lower layer. + a) POSIX mandates updating st_atime for reads. This is currently not + done in the case when the file resides on a lower layer. -b) If a file residing on a lower layer is opened for read-only and then -memory mapped with MAP_SHARED, then subsequent changes to the file are not -reflected in the memory mapping. + b) If a file residing on a lower layer is opened for read-only and then + memory mapped with MAP_SHARED, then subsequent changes to the file are not + reflected in the memory mapping. -c) If a file residing on a lower layer is being executed, then opening that -file for write or truncating the file will not be denied with ETXTBSY. + c) If a file residing on a lower layer is being executed, then opening that + file for write or truncating the file will not be denied with ETXTBSY. The following options allow overlayfs to act more like a standards compliant filesystem: -1) "redirect_dir" +redirect_dir +```````````` Enabled with the mount option or module option: "redirect_dir=on" or with the kernel config option CONFIG_OVERLAY_FS_REDIRECT_DIR=y. @@ -568,7 +569,8 @@ the kernel config option CONFIG_OVERLAY_FS_REDIRECT_DIR=y. If this feature is disabled, then rename(2) on a lower or merged directory will fail with EXDEV ("Invalid cross-device link"). -2) "inode index" +index +````` Enabled with the mount option or module option "index=on" or with the kernel config option CONFIG_OVERLAY_FS_INDEX=y. @@ -577,7 +579,8 @@ If this feature is disabled and a file with multiple hard links is copied up, then this will "break" the link. Changes will not be propagated to other names referring to the same inode. -3) "xino" +xino +```` Enabled with the mount option "xino=auto" or "xino=on", with the module option "xino_auto=on" or with the kernel config option @@ -604,7 +607,7 @@ a crash or deadlock. Offline changes, when the overlay is not mounted, are allowed to the upper tree. Offline changes to the lower tree are only allowed if the -"metadata only copy up", "inode index", "xino" and "redirect_dir" features +"metacopy", "index", "xino" and "redirect_dir" features have not been used. If the lower tree is modified and any of these features has been used, the behavior of the overlay is undefined, though it will not result in a crash or deadlock. @@ -644,12 +647,13 @@ directory inode. When encoding a file handle from an overlay filesystem object, the following rules apply: -1. For a non-upper object, encode a lower file handle from lower inode -2. For an indexed object, encode a lower file handle from copy_up origin -3. For a pure-upper object and for an existing non-indexed upper object, - encode an upper file handle from upper inode + 1. For a non-upper object, encode a lower file handle from lower inode + 2. For an indexed object, encode a lower file handle from copy_up origin + 3. For a pure-upper object and for an existing non-indexed upper object, + encode an upper file handle from upper inode The encoded overlay file handle includes: + - Header including path type information (e.g. lower/upper) - UUID of the underlying filesystem - Underlying filesystem encoding of underlying inode @@ -659,15 +663,15 @@ are stored in extended attribute "trusted.overlay.origin". When decoding an overlay file handle, the following steps are followed: -1. Find underlying layer by UUID and path type information. -2. Decode the underlying filesystem file handle to underlying dentry. -3. For a lower file handle, lookup the handle in index directory by name. -4. If a whiteout is found in index, return ESTALE. This represents an - overlay object that was deleted after its file handle was encoded. -5. For a non-directory, instantiate a disconnected overlay dentry from the - decoded underlying dentry, the path type and index inode, if found. -6. For a directory, use the connected underlying decoded dentry, path type - and index, to lookup a connected overlay dentry. + 1. Find underlying layer by UUID and path type information. + 2. Decode the underlying filesystem file handle to underlying dentry. + 3. For a lower file handle, lookup the handle in index directory by name. + 4. If a whiteout is found in index, return ESTALE. This represents an + overlay object that was deleted after its file handle was encoded. + 5. For a non-directory, instantiate a disconnected overlay dentry from the + decoded underlying dentry, the path type and index inode, if found. + 6. For a directory, use the connected underlying decoded dentry, path type + and index, to lookup a connected overlay dentry. Decoding a non-directory file handle may return a disconnected dentry. copy_up of that disconnected dentry will create an upper index entry with @@ -770,9 +774,9 @@ Testsuite There's a testsuite originally developed by David Howells and currently maintained by Amir Goldstein at: - https://github.com/amir73il/unionmount-testsuite.git +https://github.com/amir73il/unionmount-testsuite.git -Run as root: +Run as root:: # cd unionmount-testsuite # ./run --ov --verify diff --git a/Documentation/filesystems/porting.rst b/Documentation/filesystems/porting.rst index 878e72b2f8b7..ced3a6761329 100644 --- a/Documentation/filesystems/porting.rst +++ b/Documentation/filesystems/porting.rst @@ -1061,3 +1061,15 @@ export_operations ->encode_fh() no longer has a default implementation to encode FILEID_INO32_GEN* file handles. Filesystems that used the default implementation may use the generic helper generic_encode_ino32_fh() explicitly. + +--- + +**recommended** + +Block device freezing and thawing have been moved to holder operations. + +Before this change, get_active_super() would only be able to find the +superblock of the main block device, i.e., the one stored in sb->s_bdev. Block +device freezing now works for any block device owned by a given superblock, not +just the main block device. The get_active_super() helper and bd_fsfreeze_sb +pointer are gone. diff --git a/Documentation/filesystems/proc.rst b/Documentation/filesystems/proc.rst index 49ef12df631b..104c6d047d9b 100644 --- a/Documentation/filesystems/proc.rst +++ b/Documentation/filesystems/proc.rst @@ -528,9 +528,9 @@ replaced by copy-on-write) part of the underlying shmem object out on swap. does not take into account swapped out page of underlying shmem objects. "Locked" indicates whether the mapping is locked in memory or not. -"THPeligible" indicates whether the mapping is eligible for allocating THP -pages as well as the THP is PMD mappable or not - 1 if true, 0 otherwise. -It just shows the current status. +"THPeligible" indicates whether the mapping is eligible for allocating +naturally aligned THP pages of any currently enabled size. 1 if true, 0 +otherwise. "VmFlags" field deserves a separate description. This member represents the kernel flags associated with the particular virtual memory area in two letter diff --git a/Documentation/filesystems/squashfs.rst b/Documentation/filesystems/squashfs.rst index df42106bae71..4af8d6207509 100644 --- a/Documentation/filesystems/squashfs.rst +++ b/Documentation/filesystems/squashfs.rst @@ -64,6 +64,66 @@ obtained from this site also. The squashfs-tools development tree is now located on kernel.org git://git.kernel.org/pub/scm/fs/squashfs/squashfs-tools.git +2.1 Mount options +----------------- +=================== ========================================================= +errors=%s Specify whether squashfs errors trigger a kernel panic + or not + + ========== ============================================= + continue errors don't trigger a panic (default) + panic trigger a panic when errors are encountered, + similar to several other filesystems (e.g. + btrfs, ext4, f2fs, GFS2, jfs, ntfs, ubifs) + + This allows a kernel dump to be saved, + useful for analyzing and debugging the + corruption. + ========== ============================================= +threads=%s Select the decompression mode or the number of threads + + If SQUASHFS_CHOICE_DECOMP_BY_MOUNT is set: + + ========== ============================================= + single use single-threaded decompression (default) + + Only one block (data or metadata) can be + decompressed at any one time. This limits + CPU and memory usage to a minimum, but it + also gives poor performance on parallel I/O + workloads when using multiple CPU machines + due to waiting on decompressor availability. + multi use up to two parallel decompressors per core + + If you have a parallel I/O workload and your + system has enough memory, using this option + may improve overall I/O performance. It + dynamically allocates decompressors on a + demand basis. + percpu use a maximum of one decompressor per core + + It uses percpu variables to ensure + decompression is load-balanced across the + cores. + 1|2|3|... configure the number of threads used for + decompression + + The upper limit is num_online_cpus() * 2. + ========== ============================================= + + If SQUASHFS_CHOICE_DECOMP_BY_MOUNT is **not** set and + SQUASHFS_DECOMP_MULTI, SQUASHFS_MOUNT_DECOMP_THREADS are + both set: + + ========== ============================================= + 2|3|... configure the number of threads used for + decompression + + The upper limit is num_online_cpus() * 2. + ========== ============================================= + +=================== ========================================================= + 3. Squashfs Filesystem Design ----------------------------- diff --git a/Documentation/filesystems/vfs.rst b/Documentation/filesystems/vfs.rst index 276a219ff8d9..eebcc0f9e2bc 100644 --- a/Documentation/filesystems/vfs.rst +++ b/Documentation/filesystems/vfs.rst @@ -823,7 +823,7 @@ cache in your filesystem. The following members are defined: bool (*is_partially_uptodate) (struct folio *, size_t from, size_t count); void (*is_dirty_writeback)(struct folio *, bool *, bool *); - int (*error_remove_page) (struct mapping *mapping, struct page *page); + int (*error_remove_folio)(struct mapping *mapping, struct folio *); int (*swap_activate)(struct swap_info_struct *sis, struct file *f, sector_t *span) int (*swap_deactivate)(struct file *); int (*swap_rw)(struct kiocb *iocb, struct iov_iter *iter); @@ -1034,8 +1034,8 @@ cache in your filesystem. The following members are defined: VM if a folio should be treated as dirty or writeback for the purposes of stalling. -``error_remove_page`` - normally set to generic_error_remove_page if truncation is ok +``error_remove_folio`` + normally set to generic_error_remove_folio if truncation is ok for this address space. Used for memory failure handling. Setting this implies you deal with pages going away under you, unless you have them locked or reference counts increased. diff --git a/Documentation/filesystems/xfs/index.rst b/Documentation/filesystems/xfs/index.rst new file mode 100644 index 000000000000..ab66c57a5d18 --- /dev/null +++ b/Documentation/filesystems/xfs/index.rst @@ -0,0 +1,14 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============================ +XFS Filesystem Documentation +============================ + +.. toctree:: + :maxdepth: 2 + :numbered: + + xfs-delayed-logging-design + xfs-maintainer-entry-profile + xfs-self-describing-metadata + xfs-online-fsck-design diff --git a/Documentation/filesystems/xfs-delayed-logging-design.rst b/Documentation/filesystems/xfs/xfs-delayed-logging-design.rst index 6402ab8e370c..6402ab8e370c 100644 --- a/Documentation/filesystems/xfs-delayed-logging-design.rst +++ b/Documentation/filesystems/xfs/xfs-delayed-logging-design.rst diff --git a/Documentation/filesystems/xfs-maintainer-entry-profile.rst b/Documentation/filesystems/xfs/xfs-maintainer-entry-profile.rst index 32b6ac4ca9d6..32b6ac4ca9d6 100644 --- a/Documentation/filesystems/xfs-maintainer-entry-profile.rst +++ b/Documentation/filesystems/xfs/xfs-maintainer-entry-profile.rst diff --git a/Documentation/filesystems/xfs-online-fsck-design.rst b/Documentation/filesystems/xfs/xfs-online-fsck-design.rst index a0678101a7d0..352516feef6f 100644 --- a/Documentation/filesystems/xfs-online-fsck-design.rst +++ b/Documentation/filesystems/xfs/xfs-online-fsck-design.rst @@ -962,7 +962,7 @@ disk, but these buffer verifiers cannot provide any consistency checking between metadata structures. For more information, please see the documentation for -Documentation/filesystems/xfs-self-describing-metadata.rst +Documentation/filesystems/xfs/xfs-self-describing-metadata.rst Reverse Mapping --------------- diff --git a/Documentation/filesystems/xfs-self-describing-metadata.rst b/Documentation/filesystems/xfs/xfs-self-describing-metadata.rst index a10c4ae6955e..a10c4ae6955e 100644 --- a/Documentation/filesystems/xfs-self-describing-metadata.rst +++ b/Documentation/filesystems/xfs/xfs-self-describing-metadata.rst |