diff options
Diffstat (limited to 'Documentation/filesystems')
| -rw-r--r-- | Documentation/filesystems/Locking | 2 | ||||
| -rw-r--r-- | Documentation/filesystems/cramfs.txt | 2 | ||||
| -rw-r--r-- | Documentation/filesystems/porting | 53 | ||||
| -rw-r--r-- | Documentation/filesystems/tmpfs.txt | 2 | ||||
| -rw-r--r-- | Documentation/filesystems/vfs.txt | 6 |
5 files changed, 59 insertions, 6 deletions
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking index 619af9bfdcb3..75eea7ce3d7c 100644 --- a/Documentation/filesystems/Locking +++ b/Documentation/filesystems/Locking @@ -194,7 +194,7 @@ prototypes: void (*invalidatepage) (struct page *, unsigned int, unsigned int); int (*releasepage) (struct page *, int); void (*freepage)(struct page *); - int (*direct_IO)(struct kiocb *, struct iov_iter *iter, loff_t offset); + int (*direct_IO)(struct kiocb *, struct iov_iter *iter); int (*migratepage)(struct address_space *, struct page *, struct page *); int (*launder_page)(struct page *); int (*is_partially_uptodate)(struct page *, unsigned long, unsigned long); diff --git a/Documentation/filesystems/cramfs.txt b/Documentation/filesystems/cramfs.txt index 31f53f0ab957..4006298f6707 100644 --- a/Documentation/filesystems/cramfs.txt +++ b/Documentation/filesystems/cramfs.txt @@ -38,7 +38,7 @@ the update lasts only as long as the inode is cached in memory, after which the timestamp reverts to 1970, i.e. moves backwards in time. Currently, cramfs must be written and read with architectures of the -same endianness, and can be read only by kernels with PAGE_CACHE_SIZE +same endianness, and can be read only by kernels with PAGE_SIZE == 4096. At least the latter of these is a bug, but it hasn't been decided what the best fix is. For the moment if you have larger pages you can just change the #define in mkcramfs.c, so long as you don't diff --git a/Documentation/filesystems/porting b/Documentation/filesystems/porting index f1b87d8aa2da..46f3bb7a02f5 100644 --- a/Documentation/filesystems/porting +++ b/Documentation/filesystems/porting @@ -525,3 +525,56 @@ in your dentry operations instead. set_delayed_call() where it used to set *cookie. ->put_link() is gone - just give the destructor to set_delayed_call() in ->get_link(). +-- +[mandatory] + ->getxattr() and xattr_handler.get() get dentry and inode passed separately. + 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. +-- +[mandatory] + symlinks are no longer the only inodes that do *not* have i_bdev/i_cdev/ + i_pipe/i_link union zeroed out at inode eviction. As the result, you can't + assume that non-NULL value in ->i_nlink at ->destroy_inode() implies that + it's a symlink. Checking ->i_mode is really needed now. In-tree we had + to fix shmem_destroy_callback() that used to take that kind of shortcut; + watch out, since that shortcut is no longer valid. +-- +[mandatory] + ->i_mutex is replaced with ->i_rwsem now. inode_lock() et.al. work as + they used to - they just take it exclusive. However, ->lookup() may be + called with parent locked shared. Its instances must not + * use d_instantiate) and d_rehash() separately - use d_add() or + d_splice_alias() instead. + * use d_rehash() alone - call d_add(new_dentry, NULL) instead. + * in the unlikely case when (read-only) access to filesystem + data structures needs exclusion for some reason, arrange it + yourself. None of the in-tree filesystems needed that. + * rely on ->d_parent and ->d_name not changing after dentry has + been fed to d_add() or d_splice_alias(). Again, none of the + in-tree instances relied upon that. + We are guaranteed that lookups of the same name in the same directory + will not happen in parallel ("same" in the sense of your ->d_compare()). + Lookups on different names in the same directory can and do happen in + parallel now. +-- +[recommended] + ->iterate_shared() is added; it's a parallel variant of ->iterate(). + Exclusion on struct file level is still provided (as well as that + between it and lseek on the same struct file), but if your directory + has been opened several times, you can get these called in parallel. + Exclusion between that method and all directory-modifying ones is + still provided, of course. + + Often enough ->iterate() can serve as ->iterate_shared() without any + changes - it is a read-only operation, after all. If you have any + per-inode or per-dentry in-core data structures modified by ->iterate(), + you might need something to serialize the access to them. If you + do dcache pre-seeding, you'll need to switch to d_alloc_parallel() for + that; look for in-tree examples. + + Old method is only used if the new one is absent; eventually it will + be removed. Switch while you still can; the old one won't stay. +-- +[mandatory] + ->atomic_open() calls without O_CREAT may happen in parallel. diff --git a/Documentation/filesystems/tmpfs.txt b/Documentation/filesystems/tmpfs.txt index d392e1505f17..d9c11d25bf02 100644 --- a/Documentation/filesystems/tmpfs.txt +++ b/Documentation/filesystems/tmpfs.txt @@ -60,7 +60,7 @@ size: The limit of allocated bytes for this tmpfs instance. The default is half of your physical RAM without swap. If you oversize your tmpfs instances the machine will deadlock since the OOM handler will not be able to free that memory. -nr_blocks: The same as size, but in blocks of PAGE_CACHE_SIZE. +nr_blocks: The same as size, but in blocks of PAGE_SIZE. nr_inodes: The maximum number of inodes for this instance. The default is half of the number of your physical RAM pages, or (on a machine with highmem) the number of lowmem RAM pages, diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt index b02a7d598258..c61a223ef3ff 100644 --- a/Documentation/filesystems/vfs.txt +++ b/Documentation/filesystems/vfs.txt @@ -591,7 +591,7 @@ struct address_space_operations { void (*invalidatepage) (struct page *, unsigned int, unsigned int); int (*releasepage) (struct page *, int); void (*freepage)(struct page *); - ssize_t (*direct_IO)(struct kiocb *, struct iov_iter *iter, loff_t offset); + ssize_t (*direct_IO)(struct kiocb *, struct iov_iter *iter); /* migrate the contents of a page to the specified target */ int (*migratepage) (struct page *, struct page *); int (*launder_page) (struct page *); @@ -708,9 +708,9 @@ struct address_space_operations { from the address space. This generally corresponds to either a truncation, punch hole or a complete invalidation of the address space (in the latter case 'offset' will always be 0 and 'length' - will be PAGE_CACHE_SIZE). Any private data associated with the page + will be PAGE_SIZE). Any private data associated with the page should be updated to reflect this truncation. If offset is 0 and - length is PAGE_CACHE_SIZE, then the private data should be released, + length is PAGE_SIZE, then the private data should be released, because the page must be able to be completely discarded. This may be done by calling the ->releasepage function, but in this case the release MUST succeed. |