kernel/linux.git/include/uapi/linux/gfs2_ondisk.h, branch v6.12.80

gfs2: Add trusted xattr support

2021-02-08T12:01:24+00:00

Add support for an additional filesystem version (sb_fs_format = 1802). When a filesystem with the new version is mounted, the filesystem supports "trusted.*" xattrs. In addition, version 1802 filesystems implement a form of forward compatibility for xattrs: when xattrs with an unknown prefix (ea_type) are found on a version 1802 filesystem, those attributes are not shown by listxattr, and they are not accessible by getxattr, setxattr, or removexattr. This mechanism might turn out to be what we need in the future, but if not, we can always bump the filesystem version and break compatibility instead. Signed-off-by: Andreas Gruenbacher Signed-off-by: Andrew Price

gfs2: Keep track of deleted inode generations in LVBs

2020-06-05T18:19:20+00:00

When deleting an inode, keep track of the generation of the deleted inode in the inode glock Lock Value Block (LVB). When trying to delete an inode remotely, check the last-known inode generation against the deleted inode generation to skip duplicate remote deletes. This avoids taking the resource group glock in order to verify the block type. Signed-off-by: Andreas Gruenbacher

GFS2: Log the reason for log flushes in every log header

2018-01-23T14:39:20+00:00

This patch just adds the capability for GFS2 to track which function called gfs2_log_flush. This should make it easier to diagnose problems based on the sequence of events found in the journals. Signed-off-by: Bob Peterson Reviewed-by: Andreas Gruenbacher

GFS2: Introduce new gfs2_log_header_v2

2018-01-23T14:38:53+00:00

This patch adds a new structure called gfs2_log_header_v2 which is used to store expanded fields into previously unused areas of the log headers (i.e., this change is backwards compatible). Some of these are used for debug purposes so we can backtrack when problems occur. Others are reserved for future expansion. This patch is based on a prototype from Steve Whitehouse. Signed-off-by: Bob Peterson Signed-off-by: Andreas Gruenbacher

gfs2: Add a crc field to resource group headers

2017-12-12T17:43:42+00:00

Add the rg_crc field to store a crc32 of the gfs2_rgrp structure. This allows us to check resource group headers' integrity and removes the requirement to check them against the rindex entries in fsck. If this field is found to be zero, it should be ignored (or updated with an accurate value). Signed-off-by: Andrew Price Signed-off-by: Bob Peterson

gfs2: Add rindex fields to rgrp headers

2017-12-12T17:43:36+00:00

Add rg_data0, rg_data and rg_bitbytes to struct gfs2_rgrp. The fields are identical to their counterparts in struct gfs2_rindex and are intended to reduce the use of the rindex. For now the fields are only written back as the in-memory equivalents in struct gfs2_rgrpd are set using values from the rindex. However, they are needed at this point so that userspace can make use of them, allowing a migration away from the rindex over time. The new fields take up previously reserved space which was explicitly zeroed on write so, in clusters with mixed kernels, these fields could get zeroed after being set and this should not be treated as an error. Signed-off-by: Andrew Price Signed-off-by: Bob Peterson

gfs2: Add a next-resource-group pointer to resource groups

2017-12-12T17:43:08+00:00

Add a new rg_skip field to struct gfs2_rgrp, replacing __pad. The rg_skip field has the following meaning: - If rg_skip is zero, it is considered unset and not useful. - If rg_skip is non-zero, its value will be the number of blocks between this rgrp's address and the next rgrp's address. This can be used as a hint by fsck.gfs2 when rebuilding a bad rindex, for example. This will provide less dependency on the rindex in future, and allow tools such as fsck.gfs2 to iterate the resource groups without keeping the rindex around. The field is updated in gfs2_rgrp_out() so that existing file systems will have it set. This means that any resource groups that aren't ever written will not be updated. The final rgrp is a special case as there is no next rgrp, so it will always have a rg_skip of 0 (unless the fs is extended). Before this patch, gfs2_rgrp_out() zeroes the __pad field explicitly, so the rg_skip field can get set back to 0 in cases where nodes with and without this patch are mixed in a cluster. In some cases, the field may bounce between being set by one node and then zeroed by another which may harm performance slightly, e.g. when two nodes create many small files. In testing this situation is rare but it becomes more likely as the filesystem fills up and there are fewer resource groups to choose from. The problem goes away when all nodes are running with this patch. Dipping into the space currently occupied by the rg_reserved field would have resulted in the same problem as it is also explicitly zeroed, so unfortunately there is no other way around it. Signed-off-by: Andrew Price Signed-off-by: Bob Peterson

License cleanup: add SPDX license identifier to uapi header files with a license

2017-11-02T10:20:11+00:00

Many user space API headers have licensing information, which is either incomplete, badly formatted or just a shorthand for referring to the license under which the file is supposed to be. This makes it hard for compliance tools to determine the correct license. Update these files with an SPDX license identifier. The identifier was chosen based on the license information in the file. GPL/LGPL licensed headers get the matching GPL/LGPL SPDX license identifier with the added 'WITH Linux-syscall-note' exception, which is the officially assigned exception identifier for the kernel syscall exception: NOTE! This copyright does *not* cover user programs that use kernel services by normal system calls - this is merely considered normal use of the kernel, and does *not* fall under the heading of "derived work". This exception makes it possible to include GPL headers into non GPL code, without confusing license compliance tools. Headers which have either explicit dual licensing or are just licensed under a non GPL license are updated with the corresponding SPDX identifier and the GPLv2 with syscall exception identifier. The format is: ((GPL-2.0 WITH Linux-syscall-note) OR SPDX-ID-OF-OTHER-LICENSE) SPDX license identifiers are a legally binding shorthand, which can be used instead of the full boiler plate text. The update does not remove existing license information as this has to be done on a case by case basis and the copyright holders might have to be consulted. This will happen in a separate step. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. See the previous patch in this series for the methodology of how this patch was researched. Reviewed-by: Kate Stewart Reviewed-by: Philippe Ombredanne Reviewed-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

gfs2: change gfs2 readdir cookie

2015-12-14T18:19:37+00:00

gfs2 currently returns 31 bits of filename hash as a cookie that readdir uses for an offset into the directory. When there are a large number of directory entries, the likelihood of a collision goes up way too quickly. GFS2 will now return cookies that are guaranteed unique for a while, and then fail back to using 30 bits of filename hash. Specifically, the directory leaf blocks are divided up into chunks based on the minimum size of a gfs2 directory entry (48 bytes). Each entry's cookie is based off the chunk where it starts, in the linked list of leaf blocks that it hashes to (there are 131072 hash buckets). Directory entries will have unique names until they take reach chunk 8192. Assuming the largest filenames possible, and the least efficient spacing possible, this new method will still be able to return unique names when the previous method has statistically more than a 99% chance of a collision. The non-unique names it fails back to are guaranteed to not collide with the unique names. unique cookies will be in this format: - 1 bit "0" to make sure the the returned cookie is positive - 17 bits for the hash table index - 1 bit for the mode "0" - 13 bits for the offset non-unique cookies will be in this format: - 1 bit "0" to make sure the the returned cookie is positive - 17 bits for the hash table index - 1 bit for the mode "1" - 13 more bits of the name hash Another benefit of location based cookies, is that once a directory's exhash table is fully extended (so that multiple hash table indexs do not use the same leaf blocks), gfs2 can skip sorting the directory entries until it reaches the non-unique ones, and then it only needs to sort these. This provides a significant speed up for directory reads of very large directories. The only issue is that for these cookies to continue to point to the correct entry as files are added and removed from the directory, gfs2 must keep the entries at the same offset in the leaf block when they are split (see my previous patch). This means that until all the nodes in a cluster are running with code that will split the directory leaf blocks this way, none of the nodes can use the new cookie code. To deal with this, gfs2 now has the mount option loccookie, which, if set, will make it return these new location based cookies. This option must not be set until all nodes in the cluster are at least running this version of the kernel code, and you have guaranteed that there are no outstanding cookies required by other software, such as NFS. gfs2 uses some of the extra space at the end of the gfs2_dirent structure to store the calculated readdir cookies. This keeps us from needing to allocate a seperate array to hold these values. gfs2 recomputes the cookie stored in de_cookie for every readdir call. The time it takes to do so is small, and if gfs2 expected this value to be saved on disk, the new code wouldn't work correctly on filesystems created with an earlier version of gfs2. One issue with adding de_cookie to the union in the gfs2_dirent structure is that it caused the union to align itself to a 4 byte boundary, instead of its previous 2 byte boundary. This changed the offset of de_rahead. To solve that, I pulled de_rahead out of the union, since it does not need to be there. Signed-off-by: Benjamin Marzinski Signed-off-by: Bob Peterson

GFS2: remove transaction glock

2014-05-14T09:04:34+00:00

GFS2 has a transaction glock, which must be grabbed for every transaction, whose purpose is to deal with freezing the filesystem. Aside from this involving a large amount of locking, it is very easy to make the current fsfreeze code hang on unfreezing. This patch rewrites how gfs2 handles freezing the filesystem. The transaction glock is removed. In it's place is a freeze glock, which is cached (but not held) in a shared state by every node in the cluster when the filesystem is mounted. This lock only needs to be grabbed on freezing, and actions which need to be safe from freezing, like recovery. When a node wants to freeze the filesystem, it grabs this glock exclusively. When the freeze glock state changes on the nodes (either from shared to unlocked, or shared to exclusive), the filesystem does a special log flush. gfs2_log_flush() does all the work for flushing out the and shutting down the incore log, and then it tries to grab the freeze glock in a shared state again. Since the filesystem is stuck in gfs2_log_flush, no new transaction can start, and nothing can be written to disk. Unfreezing the filesytem simply involes dropping the freeze glock, allowing gfs2_log_flush() to grab and then release the shared lock, so it is cached for next time. However, in order for the unfreezing ioctl to occur, gfs2 needs to get a shared lock on the filesystem root directory inode to check permissions. If that glock has already been grabbed exclusively, fsfreeze will be unable to get the shared lock and unfreeze the filesystem. In order to allow the unfreeze, this patch makes gfs2 grab a shared lock on the filesystem root directory during the freeze, and hold it until it unfreezes the filesystem. The functions which need to grab a shared lock in order to allow the unfreeze ioctl to be issued now use the lock grabbed by the freeze code instead. The freeze and unfreeze code take care to make sure that this shared lock will not be dropped while another process is using it. Signed-off-by: Benjamin Marzinski Signed-off-by: Steven Whitehouse