diff options
Diffstat (limited to 'Documentation/filesystems')
| -rw-r--r-- | Documentation/filesystems/Locking | 3 | ||||
| -rw-r--r-- | Documentation/filesystems/configfs/configfs.txt | 2 | ||||
| -rw-r--r-- | Documentation/filesystems/dax.txt | 22 | ||||
| -rw-r--r-- | Documentation/filesystems/ext4.txt | 13 | ||||
| -rw-r--r-- | Documentation/filesystems/locks.txt | 2 | ||||
| -rw-r--r-- | Documentation/filesystems/nfs/nfsroot.txt | 4 | ||||
| -rw-r--r-- | Documentation/filesystems/proc.txt | 39 | ||||
| -rw-r--r-- | Documentation/filesystems/vfs.txt | 1 |
8 files changed, 34 insertions, 52 deletions
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking index 14cdc101d165..69e2387ca278 100644 --- a/Documentation/filesystems/Locking +++ b/Documentation/filesystems/Locking @@ -447,7 +447,6 @@ prototypes: int (*flush) (struct file *); int (*release) (struct inode *, struct file *); int (*fsync) (struct file *, loff_t start, loff_t end, int datasync); - int (*aio_fsync) (struct kiocb *, int datasync); int (*fasync) (int, struct file *, int); int (*lock) (struct file *, int, struct file_lock *); ssize_t (*readv) (struct file *, const struct iovec *, unsigned long, @@ -557,7 +556,7 @@ till "end_pgoff". ->map_pages() is called with page table locked and must not block. If it's not possible to reach a page without blocking, filesystem should skip it. Filesystem should use do_set_pte() to setup page table entry. Pointer to entry associated with the page is passed in -"pte" field in fault_env structure. Pointers to entries for other offsets +"pte" field in vm_fault structure. Pointers to entries for other offsets should be calculated relative to "pte". ->page_mkwrite() is called when a previously read-only pte is diff --git a/Documentation/filesystems/configfs/configfs.txt b/Documentation/filesystems/configfs/configfs.txt index 8ec9136aae56..3828e85345ae 100644 --- a/Documentation/filesystems/configfs/configfs.txt +++ b/Documentation/filesystems/configfs/configfs.txt @@ -174,7 +174,7 @@ among other things. For that, it needs a type. void (*release)(struct config_item *); int (*allow_link)(struct config_item *src, struct config_item *target); - int (*drop_link)(struct config_item *src, + void (*drop_link)(struct config_item *src, struct config_item *target); }; diff --git a/Documentation/filesystems/dax.txt b/Documentation/filesystems/dax.txt index 23d18b8a49d5..a7e6e14aeb08 100644 --- a/Documentation/filesystems/dax.txt +++ b/Documentation/filesystems/dax.txt @@ -58,22 +58,22 @@ Implementation Tips for Filesystem Writers Filesystem support consists of - adding support to mark inodes as being DAX by setting the S_DAX flag in i_flags -- implementing the direct_IO address space operation, and calling - dax_do_io() instead of blockdev_direct_IO() if S_DAX is set +- implementing ->read_iter and ->write_iter operations which use dax_iomap_rw() + when inode has S_DAX flag set - implementing an mmap file operation for DAX files which sets the VM_MIXEDMAP and VM_HUGEPAGE flags on the VMA, and setting the vm_ops to - include handlers for fault, pmd_fault and page_mkwrite (which should - probably call dax_fault(), dax_pmd_fault() and dax_mkwrite(), passing the - appropriate get_block() callback) -- calling dax_truncate_page() instead of block_truncate_page() for DAX files -- calling dax_zero_page_range() instead of zero_user() for DAX files + include handlers for fault, pmd_fault, page_mkwrite, pfn_mkwrite. These + handlers should probably call dax_iomap_fault() (for fault and page_mkwrite + handlers), dax_iomap_pmd_fault(), dax_pfn_mkwrite() passing the appropriate + iomap operations. +- calling iomap_zero_range() passing appropriate iomap operations instead of + block_truncate_page() for DAX files - ensuring that there is sufficient locking between reads, writes, truncates and page faults -The get_block() callback passed to the DAX functions may return -uninitialised extents. If it does, it must ensure that simultaneous -calls to get_block() (for example by a page-fault racing with a read() -or a write()) work correctly. +The iomap handlers for allocating blocks must make sure that allocated blocks +are zeroed out and converted to written extents before being returned to avoid +exposure of uninitialized data through mmap. These filesystems may be used for inspiration: - ext2: see Documentation/filesystems/ext2.txt diff --git a/Documentation/filesystems/ext4.txt b/Documentation/filesystems/ext4.txt index 6c0108eb0137..3698ed3146e3 100644 --- a/Documentation/filesystems/ext4.txt +++ b/Documentation/filesystems/ext4.txt @@ -351,14 +351,13 @@ nouid32 Disables 32-bit UIDs and GIDs. This is for interoperability with older kernels which only store and expect 16-bit values. -block_validity This options allows to enables/disables the in-kernel +block_validity(*) These options enable or disable the in-kernel noblock_validity facility for tracking filesystem metadata blocks - within internal data structures. This allows multi- - block allocator and other routines to quickly locate - extents which might overlap with filesystem metadata - blocks. This option is intended for debugging - purposes and since it negatively affects the - performance, it is off by default. + within internal data structures. This allows multi- + block allocator and other routines to notice + bugs or corrupted allocation bitmaps which cause + blocks to be allocated which overlap with + filesystem metadata blocks. dioread_lock Controls whether or not ext4 should use the DIO read dioread_nolock locking. If the dioread_nolock option is specified diff --git a/Documentation/filesystems/locks.txt b/Documentation/filesystems/locks.txt index 2cf81082581d..5368690f412e 100644 --- a/Documentation/filesystems/locks.txt +++ b/Documentation/filesystems/locks.txt @@ -19,7 +19,7 @@ forever. This should not cause problems for anybody, since everybody using a 2.1.x kernel should have updated their C library to a suitable version -anyway (see the file "Documentation/Changes".) +anyway (see the file "Documentation/process/changes.rst".) 1.2 Allow Mixed Locks Again --------------------------- diff --git a/Documentation/filesystems/nfs/nfsroot.txt b/Documentation/filesystems/nfs/nfsroot.txt index 0b2883b17d4c..5efae00f6c7f 100644 --- a/Documentation/filesystems/nfs/nfsroot.txt +++ b/Documentation/filesystems/nfs/nfsroot.txt @@ -11,7 +11,7 @@ Updated 2006 by Horms <horms@verge.net.au> In order to use a diskless system, such as an X-terminal or printer server for example, it is necessary for the root filesystem to be present on a non-disk device. This may be an initramfs (see Documentation/filesystems/ -ramfs-rootfs-initramfs.txt), a ramdisk (see Documentation/initrd.txt) or a +ramfs-rootfs-initramfs.txt), a ramdisk (see Documentation/admin-guide/initrd.rst) or a filesystem mounted via NFS. The following text describes on how to use NFS for the root filesystem. For the rest of this text 'client' means the diskless system, and 'server' means the NFS server. @@ -284,7 +284,7 @@ They depend on various facilities being available: "kernel <relative-path-below /tftpboot>". The nfsroot parameters are passed to the kernel by adding them to the "append" line. It is common to use serial console in conjunction with pxeliunx, - see Documentation/serial-console.txt for more information. + see Documentation/admin-guide/serial-console.rst for more information. For more information on isolinux, including how to create bootdisks for prebuilt kernels, see http://syslinux.zytor.com/ diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt index 219ffd41a911..72624a16b792 100644 --- a/Documentation/filesystems/proc.txt +++ b/Documentation/filesystems/proc.txt @@ -191,6 +191,7 @@ read the file /proc/PID/status: CapPrm: 0000000000000000 CapEff: 0000000000000000 CapBnd: ffffffffffffffff + NoNewPrivs: 0 Seccomp: 0 voluntary_ctxt_switches: 0 nonvoluntary_ctxt_switches: 1 @@ -262,6 +263,7 @@ Table 1-2: Contents of the status files (as of 4.1) CapPrm bitmap of permitted capabilities CapEff bitmap of effective capabilities CapBnd bitmap of capabilities bounding set + NoNewPrivs no_new_privs, like prctl(PR_GET_NO_NEW_PRIV, ...) Seccomp seccomp mode, like prctl(PR_GET_SECCOMP, ...) Cpus_allowed mask of CPUs on which this process may run Cpus_allowed_list Same as previous, but in "list format" @@ -395,32 +397,6 @@ is not associated with a file: or if empty, the mapping is anonymous. -The /proc/PID/task/TID/maps is a view of the virtual memory from the viewpoint -of the individual tasks of a process. In this file you will see a mapping marked -as [stack] if that task sees it as a stack. Hence, for the example above, the -task-level map, i.e. /proc/PID/task/TID/maps for thread 1001 will look like this: - -08048000-08049000 r-xp 00000000 03:00 8312 /opt/test -08049000-0804a000 rw-p 00001000 03:00 8312 /opt/test -0804a000-0806b000 rw-p 00000000 00:00 0 [heap] -a7cb1000-a7cb2000 ---p 00000000 00:00 0 -a7cb2000-a7eb2000 rw-p 00000000 00:00 0 -a7eb2000-a7eb3000 ---p 00000000 00:00 0 -a7eb3000-a7ed5000 rw-p 00000000 00:00 0 [stack] -a7ed5000-a8008000 r-xp 00000000 03:00 4222 /lib/libc.so.6 -a8008000-a800a000 r--p 00133000 03:00 4222 /lib/libc.so.6 -a800a000-a800b000 rw-p 00135000 03:00 4222 /lib/libc.so.6 -a800b000-a800e000 rw-p 00000000 00:00 0 -a800e000-a8022000 r-xp 00000000 03:00 14462 /lib/libpthread.so.0 -a8022000-a8023000 r--p 00013000 03:00 14462 /lib/libpthread.so.0 -a8023000-a8024000 rw-p 00014000 03:00 14462 /lib/libpthread.so.0 -a8024000-a8027000 rw-p 00000000 00:00 0 -a8027000-a8043000 r-xp 00000000 03:00 8317 /lib/ld-linux.so.2 -a8043000-a8044000 r--p 0001b000 03:00 8317 /lib/ld-linux.so.2 -a8044000-a8045000 rw-p 0001c000 03:00 8317 /lib/ld-linux.so.2 -aff35000-aff4a000 rw-p 00000000 00:00 0 -ffffe000-fffff000 r-xp 00000000 00:00 0 [vdso] - The /proc/PID/smaps is an extension based on maps, showing the memory consumption for each of the process's mappings. For each of mappings there is a series of lines such as the following: @@ -1331,7 +1307,16 @@ second). The meanings of the columns are as follows, from left to right: - nice: niced processes executing in user mode - system: processes executing in kernel mode - idle: twiddling thumbs -- iowait: waiting for I/O to complete +- iowait: In a word, iowait stands for waiting for I/O to complete. But there + are several problems: + 1. Cpu will not wait for I/O to complete, iowait is the time that a task is + waiting for I/O to complete. When cpu goes into idle state for + outstanding task io, another task will be scheduled on this CPU. + 2. In a multi-core CPU, the task waiting for I/O to complete is not running + on any CPU, so the iowait of each CPU is difficult to calculate. + 3. The value of iowait field in /proc/stat will decrease in certain + conditions. + So, the iowait is not reliable by reading from /proc/stat. - irq: servicing interrupts - softirq: servicing softirqs - steal: involuntary wait diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt index d619c8d71966..b5039a00caaf 100644 --- a/Documentation/filesystems/vfs.txt +++ b/Documentation/filesystems/vfs.txt @@ -828,7 +828,6 @@ struct file_operations { int (*flush) (struct file *, fl_owner_t id); int (*release) (struct inode *, struct file *); int (*fsync) (struct file *, loff_t, loff_t, int datasync); - int (*aio_fsync) (struct kiocb *, int datasync); int (*fasync) (int, struct file *, int); int (*lock) (struct file *, int, struct file_lock *); ssize_t (*sendpage) (struct file *, struct page *, int, size_t, loff_t *, int); |