diff options
Diffstat (limited to 'Documentation/filesystems')
-rw-r--r-- | Documentation/filesystems/fiemap.txt | 3 | ||||
-rw-r--r-- | Documentation/filesystems/inotify.txt | 197 | ||||
-rw-r--r-- | Documentation/filesystems/nfs/pnfs.txt | 13 | ||||
-rw-r--r-- | Documentation/filesystems/ocfs2.txt | 4 | ||||
-rw-r--r-- | Documentation/filesystems/proc.txt | 25 | ||||
-rw-r--r-- | Documentation/filesystems/seq_file.txt | 12 | ||||
-rw-r--r-- | Documentation/filesystems/xfs.txt | 22 |
7 files changed, 56 insertions, 220 deletions
diff --git a/Documentation/filesystems/fiemap.txt b/Documentation/filesystems/fiemap.txt index 1b805a0efbb0..f6d9c99103a4 100644 --- a/Documentation/filesystems/fiemap.txt +++ b/Documentation/filesystems/fiemap.txt | |||
@@ -196,7 +196,8 @@ struct fiemap_extent_info { | |||
196 | }; | 196 | }; |
197 | 197 | ||
198 | It is intended that the file system should not need to access any of this | 198 | It is intended that the file system should not need to access any of this |
199 | structure directly. | 199 | structure directly. Filesystem handlers should be tolerant to signals and return |
200 | EINTR once fatal signal received. | ||
200 | 201 | ||
201 | 202 | ||
202 | Flag checking should be done at the beginning of the ->fiemap callback via the | 203 | Flag checking should be done at the beginning of the ->fiemap callback via the |
diff --git a/Documentation/filesystems/inotify.txt b/Documentation/filesystems/inotify.txt index cfd02712b83e..51f61db787fb 100644 --- a/Documentation/filesystems/inotify.txt +++ b/Documentation/filesystems/inotify.txt | |||
@@ -4,201 +4,10 @@ | |||
4 | 4 | ||
5 | 5 | ||
6 | Document started 15 Mar 2005 by Robert Love <rml@novell.com> | 6 | Document started 15 Mar 2005 by Robert Love <rml@novell.com> |
7 | Document updated 4 Jan 2015 by Zhang Zhen <zhenzhang.zhang@huawei.com> | ||
8 | --Deleted obsoleted interface, just refer to manpages for user interface. | ||
7 | 9 | ||
8 | 10 | (i) Rationale | |
9 | (i) User Interface | ||
10 | |||
11 | Inotify is controlled by a set of three system calls and normal file I/O on a | ||
12 | returned file descriptor. | ||
13 | |||
14 | First step in using inotify is to initialise an inotify instance: | ||
15 | |||
16 | int fd = inotify_init (); | ||
17 | |||
18 | Each instance is associated with a unique, ordered queue. | ||
19 | |||
20 | Change events are managed by "watches". A watch is an (object,mask) pair where | ||
21 | the object is a file or directory and the mask is a bit mask of one or more | ||
22 | inotify events that the application wishes to receive. See <linux/inotify.h> | ||
23 | for valid events. A watch is referenced by a watch descriptor, or wd. | ||
24 | |||
25 | Watches are added via a path to the file. | ||
26 | |||
27 | Watches on a directory will return events on any files inside of the directory. | ||
28 | |||
29 | Adding a watch is simple: | ||
30 | |||
31 | int wd = inotify_add_watch (fd, path, mask); | ||
32 | |||
33 | Where "fd" is the return value from inotify_init(), path is the path to the | ||
34 | object to watch, and mask is the watch mask (see <linux/inotify.h>). | ||
35 | |||
36 | You can update an existing watch in the same manner, by passing in a new mask. | ||
37 | |||
38 | An existing watch is removed via | ||
39 | |||
40 | int ret = inotify_rm_watch (fd, wd); | ||
41 | |||
42 | Events are provided in the form of an inotify_event structure that is read(2) | ||
43 | from a given inotify instance. The filename is of dynamic length and follows | ||
44 | the struct. It is of size len. The filename is padded with null bytes to | ||
45 | ensure proper alignment. This padding is reflected in len. | ||
46 | |||
47 | You can slurp multiple events by passing a large buffer, for example | ||
48 | |||
49 | size_t len = read (fd, buf, BUF_LEN); | ||
50 | |||
51 | Where "buf" is a pointer to an array of "inotify_event" structures at least | ||
52 | BUF_LEN bytes in size. The above example will return as many events as are | ||
53 | available and fit in BUF_LEN. | ||
54 | |||
55 | Each inotify instance fd is also select()- and poll()-able. | ||
56 | |||
57 | You can find the size of the current event queue via the standard FIONREAD | ||
58 | ioctl on the fd returned by inotify_init(). | ||
59 | |||
60 | All watches are destroyed and cleaned up on close. | ||
61 | |||
62 | |||
63 | (ii) | ||
64 | |||
65 | Prototypes: | ||
66 | |||
67 | int inotify_init (void); | ||
68 | int inotify_add_watch (int fd, const char *path, __u32 mask); | ||
69 | int inotify_rm_watch (int fd, __u32 mask); | ||
70 | |||
71 | |||
72 | (iii) Kernel Interface | ||
73 | |||
74 | Inotify's kernel API consists a set of functions for managing watches and an | ||
75 | event callback. | ||
76 | |||
77 | To use the kernel API, you must first initialize an inotify instance with a set | ||
78 | of inotify_operations. You are given an opaque inotify_handle, which you use | ||
79 | for any further calls to inotify. | ||
80 | |||
81 | struct inotify_handle *ih = inotify_init(my_event_handler); | ||
82 | |||
83 | You must provide a function for processing events and a function for destroying | ||
84 | the inotify watch. | ||
85 | |||
86 | void handle_event(struct inotify_watch *watch, u32 wd, u32 mask, | ||
87 | u32 cookie, const char *name, struct inode *inode) | ||
88 | |||
89 | watch - the pointer to the inotify_watch that triggered this call | ||
90 | wd - the watch descriptor | ||
91 | mask - describes the event that occurred | ||
92 | cookie - an identifier for synchronizing events | ||
93 | name - the dentry name for affected files in a directory-based event | ||
94 | inode - the affected inode in a directory-based event | ||
95 | |||
96 | void destroy_watch(struct inotify_watch *watch) | ||
97 | |||
98 | You may add watches by providing a pre-allocated and initialized inotify_watch | ||
99 | structure and specifying the inode to watch along with an inotify event mask. | ||
100 | You must pin the inode during the call. You will likely wish to embed the | ||
101 | inotify_watch structure in a structure of your own which contains other | ||
102 | information about the watch. Once you add an inotify watch, it is immediately | ||
103 | subject to removal depending on filesystem events. You must grab a reference if | ||
104 | you depend on the watch hanging around after the call. | ||
105 | |||
106 | inotify_init_watch(&my_watch->iwatch); | ||
107 | inotify_get_watch(&my_watch->iwatch); // optional | ||
108 | s32 wd = inotify_add_watch(ih, &my_watch->iwatch, inode, mask); | ||
109 | inotify_put_watch(&my_watch->iwatch); // optional | ||
110 | |||
111 | You may use the watch descriptor (wd) or the address of the inotify_watch for | ||
112 | other inotify operations. You must not directly read or manipulate data in the | ||
113 | inotify_watch. Additionally, you must not call inotify_add_watch() more than | ||
114 | once for a given inotify_watch structure, unless you have first called either | ||
115 | inotify_rm_watch() or inotify_rm_wd(). | ||
116 | |||
117 | To determine if you have already registered a watch for a given inode, you may | ||
118 | call inotify_find_watch(), which gives you both the wd and the watch pointer for | ||
119 | the inotify_watch, or an error if the watch does not exist. | ||
120 | |||
121 | wd = inotify_find_watch(ih, inode, &watchp); | ||
122 | |||
123 | You may use container_of() on the watch pointer to access your own data | ||
124 | associated with a given watch. When an existing watch is found, | ||
125 | inotify_find_watch() bumps the refcount before releasing its locks. You must | ||
126 | put that reference with: | ||
127 | |||
128 | put_inotify_watch(watchp); | ||
129 | |||
130 | Call inotify_find_update_watch() to update the event mask for an existing watch. | ||
131 | inotify_find_update_watch() returns the wd of the updated watch, or an error if | ||
132 | the watch does not exist. | ||
133 | |||
134 | wd = inotify_find_update_watch(ih, inode, mask); | ||
135 | |||
136 | An existing watch may be removed by calling either inotify_rm_watch() or | ||
137 | inotify_rm_wd(). | ||
138 | |||
139 | int ret = inotify_rm_watch(ih, &my_watch->iwatch); | ||
140 | int ret = inotify_rm_wd(ih, wd); | ||
141 | |||
142 | A watch may be removed while executing your event handler with the following: | ||
143 | |||
144 | inotify_remove_watch_locked(ih, iwatch); | ||
145 | |||
146 | Call inotify_destroy() to remove all watches from your inotify instance and | ||
147 | release it. If there are no outstanding references, inotify_destroy() will call | ||
148 | your destroy_watch op for each watch. | ||
149 | |||
150 | inotify_destroy(ih); | ||
151 | |||
152 | When inotify removes a watch, it sends an IN_IGNORED event to your callback. | ||
153 | You may use this event as an indication to free the watch memory. Note that | ||
154 | inotify may remove a watch due to filesystem events, as well as by your request. | ||
155 | If you use IN_ONESHOT, inotify will remove the watch after the first event, at | ||
156 | which point you may call the final inotify_put_watch. | ||
157 | |||
158 | (iv) Kernel Interface Prototypes | ||
159 | |||
160 | struct inotify_handle *inotify_init(struct inotify_operations *ops); | ||
161 | |||
162 | inotify_init_watch(struct inotify_watch *watch); | ||
163 | |||
164 | s32 inotify_add_watch(struct inotify_handle *ih, | ||
165 | struct inotify_watch *watch, | ||
166 | struct inode *inode, u32 mask); | ||
167 | |||
168 | s32 inotify_find_watch(struct inotify_handle *ih, struct inode *inode, | ||
169 | struct inotify_watch **watchp); | ||
170 | |||
171 | s32 inotify_find_update_watch(struct inotify_handle *ih, | ||
172 | struct inode *inode, u32 mask); | ||
173 | |||
174 | int inotify_rm_wd(struct inotify_handle *ih, u32 wd); | ||
175 | |||
176 | int inotify_rm_watch(struct inotify_handle *ih, | ||
177 | struct inotify_watch *watch); | ||
178 | |||
179 | void inotify_remove_watch_locked(struct inotify_handle *ih, | ||
180 | struct inotify_watch *watch); | ||
181 | |||
182 | void inotify_destroy(struct inotify_handle *ih); | ||
183 | |||
184 | void get_inotify_watch(struct inotify_watch *watch); | ||
185 | void put_inotify_watch(struct inotify_watch *watch); | ||
186 | |||
187 | |||
188 | (v) Internal Kernel Implementation | ||
189 | |||
190 | Each inotify instance is represented by an inotify_handle structure. | ||
191 | Inotify's userspace consumers also have an inotify_device which is | ||
192 | associated with the inotify_handle, and on which events are queued. | ||
193 | |||
194 | Each watch is associated with an inotify_watch structure. Watches are chained | ||
195 | off of each associated inotify_handle and each associated inode. | ||
196 | |||
197 | See fs/notify/inotify/inotify_fsnotify.c and fs/notify/inotify/inotify_user.c | ||
198 | for the locking and lifetime rules. | ||
199 | |||
200 | |||
201 | (vi) Rationale | ||
202 | 11 | ||
203 | Q: What is the design decision behind not tying the watch to the open fd of | 12 | Q: What is the design decision behind not tying the watch to the open fd of |
204 | the watched object? | 13 | the watched object? |
diff --git a/Documentation/filesystems/nfs/pnfs.txt b/Documentation/filesystems/nfs/pnfs.txt index adc81a35fe2d..44a9f2493a88 100644 --- a/Documentation/filesystems/nfs/pnfs.txt +++ b/Documentation/filesystems/nfs/pnfs.txt | |||
@@ -57,15 +57,16 @@ bit is set, preventing any new lsegs from being added. | |||
57 | layout drivers | 57 | layout drivers |
58 | -------------- | 58 | -------------- |
59 | 59 | ||
60 | PNFS utilizes what is called layout drivers. The STD defines 3 basic | 60 | PNFS utilizes what is called layout drivers. The STD defines 4 basic |
61 | layout types: "files" "objects" and "blocks". For each of these types | 61 | layout types: "files", "objects", "blocks", and "flexfiles". For each |
62 | there is a layout-driver with a common function-vectors table which | 62 | of these types there is a layout-driver with a common function-vectors |
63 | are called by the nfs-client pnfs-core to implement the different layout | 63 | table which are called by the nfs-client pnfs-core to implement the |
64 | types. | 64 | different layout types. |
65 | 65 | ||
66 | Files-layout-driver code is in: fs/nfs/nfs4filelayout.c && nfs4filelayoutdev.c | 66 | Files-layout-driver code is in: fs/nfs/filelayout/.. directory |
67 | Objects-layout-deriver code is in: fs/nfs/objlayout/.. directory | 67 | Objects-layout-deriver code is in: fs/nfs/objlayout/.. directory |
68 | Blocks-layout-deriver code is in: fs/nfs/blocklayout/.. directory | 68 | Blocks-layout-deriver code is in: fs/nfs/blocklayout/.. directory |
69 | Flexfiles-layout-driver code is in: fs/nfs/flexfilelayout/.. directory | ||
69 | 70 | ||
70 | objects-layout setup | 71 | objects-layout setup |
71 | -------------------- | 72 | -------------------- |
diff --git a/Documentation/filesystems/ocfs2.txt b/Documentation/filesystems/ocfs2.txt index 7618a287aa41..28f8c08201e2 100644 --- a/Documentation/filesystems/ocfs2.txt +++ b/Documentation/filesystems/ocfs2.txt | |||
@@ -100,3 +100,7 @@ coherency=full (*) Disallow concurrent O_DIRECT writes, cluster inode | |||
100 | coherency=buffered Allow concurrent O_DIRECT writes without EX lock among | 100 | coherency=buffered Allow concurrent O_DIRECT writes without EX lock among |
101 | nodes, which gains high performance at risk of getting | 101 | nodes, which gains high performance at risk of getting |
102 | stale data on other nodes. | 102 | stale data on other nodes. |
103 | journal_async_commit Commit block can be written to disk without waiting | ||
104 | for descriptor blocks. If enabled older kernels cannot | ||
105 | mount the device. This will enable 'journal_checksum' | ||
106 | internally. | ||
diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt index aae9dd13c91f..cf8fc2f0b34b 100644 --- a/Documentation/filesystems/proc.txt +++ b/Documentation/filesystems/proc.txt | |||
@@ -28,7 +28,7 @@ Table of Contents | |||
28 | 1.6 Parallel port info in /proc/parport | 28 | 1.6 Parallel port info in /proc/parport |
29 | 1.7 TTY info in /proc/tty | 29 | 1.7 TTY info in /proc/tty |
30 | 1.8 Miscellaneous kernel statistics in /proc/stat | 30 | 1.8 Miscellaneous kernel statistics in /proc/stat |
31 | 1.9 Ext4 file system parameters | 31 | 1.9 Ext4 file system parameters |
32 | 32 | ||
33 | 2 Modifying System Parameters | 33 | 2 Modifying System Parameters |
34 | 34 | ||
@@ -42,6 +42,7 @@ Table of Contents | |||
42 | 3.6 /proc/<pid>/comm & /proc/<pid>/task/<tid>/comm | 42 | 3.6 /proc/<pid>/comm & /proc/<pid>/task/<tid>/comm |
43 | 3.7 /proc/<pid>/task/<tid>/children - Information about task children | 43 | 3.7 /proc/<pid>/task/<tid>/children - Information about task children |
44 | 3.8 /proc/<pid>/fdinfo/<fd> - Information about opened file | 44 | 3.8 /proc/<pid>/fdinfo/<fd> - Information about opened file |
45 | 3.9 /proc/<pid>/map_files - Information about memory mapped files | ||
45 | 46 | ||
46 | 4 Configuring procfs | 47 | 4 Configuring procfs |
47 | 4.1 Mount options | 48 | 4.1 Mount options |
@@ -1763,6 +1764,28 @@ pair provide additional information particular to the objects they represent. | |||
1763 | with TIMER_ABSTIME option which will be shown in 'settime flags', but 'it_value' | 1764 | with TIMER_ABSTIME option which will be shown in 'settime flags', but 'it_value' |
1764 | still exhibits timer's remaining time. | 1765 | still exhibits timer's remaining time. |
1765 | 1766 | ||
1767 | 3.9 /proc/<pid>/map_files - Information about memory mapped files | ||
1768 | --------------------------------------------------------------------- | ||
1769 | This directory contains symbolic links which represent memory mapped files | ||
1770 | the process is maintaining. Example output: | ||
1771 | |||
1772 | | lr-------- 1 root root 64 Jan 27 11:24 333c600000-333c620000 -> /usr/lib64/ld-2.18.so | ||
1773 | | lr-------- 1 root root 64 Jan 27 11:24 333c81f000-333c820000 -> /usr/lib64/ld-2.18.so | ||
1774 | | lr-------- 1 root root 64 Jan 27 11:24 333c820000-333c821000 -> /usr/lib64/ld-2.18.so | ||
1775 | | ... | ||
1776 | | lr-------- 1 root root 64 Jan 27 11:24 35d0421000-35d0422000 -> /usr/lib64/libselinux.so.1 | ||
1777 | | lr-------- 1 root root 64 Jan 27 11:24 400000-41a000 -> /usr/bin/ls | ||
1778 | |||
1779 | The name of a link represents the virtual memory bounds of a mapping, i.e. | ||
1780 | vm_area_struct::vm_start-vm_area_struct::vm_end. | ||
1781 | |||
1782 | The main purpose of the map_files is to retrieve a set of memory mapped | ||
1783 | files in a fast way instead of parsing /proc/<pid>/maps or | ||
1784 | /proc/<pid>/smaps, both of which contain many more records. At the same | ||
1785 | time one can open(2) mappings from the listings of two processes and | ||
1786 | comparing their inode numbers to figure out which anonymous memory areas | ||
1787 | are actually shared. | ||
1788 | |||
1766 | ------------------------------------------------------------------------------ | 1789 | ------------------------------------------------------------------------------ |
1767 | Configuring procfs | 1790 | Configuring procfs |
1768 | ------------------------------------------------------------------------------ | 1791 | ------------------------------------------------------------------------------ |
diff --git a/Documentation/filesystems/seq_file.txt b/Documentation/filesystems/seq_file.txt index b797ed38de46..9de4303201e1 100644 --- a/Documentation/filesystems/seq_file.txt +++ b/Documentation/filesystems/seq_file.txt | |||
@@ -194,16 +194,16 @@ which is in the string esc will be represented in octal form in the output. | |||
194 | 194 | ||
195 | There are also a pair of functions for printing filenames: | 195 | There are also a pair of functions for printing filenames: |
196 | 196 | ||
197 | int seq_path(struct seq_file *m, struct path *path, char *esc); | 197 | int seq_path(struct seq_file *m, const struct path *path, |
198 | int seq_path_root(struct seq_file *m, struct path *path, | 198 | const char *esc); |
199 | struct path *root, char *esc) | 199 | int seq_path_root(struct seq_file *m, const struct path *path, |
200 | const struct path *root, const char *esc) | ||
200 | 201 | ||
201 | Here, path indicates the file of interest, and esc is a set of characters | 202 | Here, path indicates the file of interest, and esc is a set of characters |
202 | which should be escaped in the output. A call to seq_path() will output | 203 | which should be escaped in the output. A call to seq_path() will output |
203 | the path relative to the current process's filesystem root. If a different | 204 | the path relative to the current process's filesystem root. If a different |
204 | root is desired, it can be used with seq_path_root(). Note that, if it | 205 | root is desired, it can be used with seq_path_root(). If it turns out that |
205 | turns out that path cannot be reached from root, the value of root will be | 206 | path cannot be reached from root, seq_path_root() returns SEQ_SKIP. |
206 | changed in seq_file_root() to a root which *does* work. | ||
207 | 207 | ||
208 | A function producing complicated output may want to check | 208 | A function producing complicated output may want to check |
209 | bool seq_has_overflowed(struct seq_file *m); | 209 | bool seq_has_overflowed(struct seq_file *m); |
diff --git a/Documentation/filesystems/xfs.txt b/Documentation/filesystems/xfs.txt index 5be51fd888bd..0bfafe108357 100644 --- a/Documentation/filesystems/xfs.txt +++ b/Documentation/filesystems/xfs.txt | |||
@@ -287,9 +287,9 @@ The following sysctls are available for the XFS filesystem: | |||
287 | XFS_ERRLEVEL_LOW: 1 | 287 | XFS_ERRLEVEL_LOW: 1 |
288 | XFS_ERRLEVEL_HIGH: 5 | 288 | XFS_ERRLEVEL_HIGH: 5 |
289 | 289 | ||
290 | fs.xfs.panic_mask (Min: 0 Default: 0 Max: 127) | 290 | fs.xfs.panic_mask (Min: 0 Default: 0 Max: 255) |
291 | Causes certain error conditions to call BUG(). Value is a bitmask; | 291 | Causes certain error conditions to call BUG(). Value is a bitmask; |
292 | AND together the tags which represent errors which should cause panics: | 292 | OR together the tags which represent errors which should cause panics: |
293 | 293 | ||
294 | XFS_NO_PTAG 0 | 294 | XFS_NO_PTAG 0 |
295 | XFS_PTAG_IFLUSH 0x00000001 | 295 | XFS_PTAG_IFLUSH 0x00000001 |
@@ -299,6 +299,7 @@ The following sysctls are available for the XFS filesystem: | |||
299 | XFS_PTAG_SHUTDOWN_CORRUPT 0x00000010 | 299 | XFS_PTAG_SHUTDOWN_CORRUPT 0x00000010 |
300 | XFS_PTAG_SHUTDOWN_IOERROR 0x00000020 | 300 | XFS_PTAG_SHUTDOWN_IOERROR 0x00000020 |
301 | XFS_PTAG_SHUTDOWN_LOGERROR 0x00000040 | 301 | XFS_PTAG_SHUTDOWN_LOGERROR 0x00000040 |
302 | XFS_PTAG_FSBLOCK_ZERO 0x00000080 | ||
302 | 303 | ||
303 | This option is intended for debugging only. | 304 | This option is intended for debugging only. |
304 | 305 | ||
@@ -348,16 +349,13 @@ The following sysctls are available for the XFS filesystem: | |||
348 | Deprecated Sysctls | 349 | Deprecated Sysctls |
349 | ================== | 350 | ================== |
350 | 351 | ||
351 | fs.xfs.xfsbufd_centisecs (Min: 50 Default: 100 Max: 3000) | 352 | None at present. |
352 | Dirty metadata is now tracked by the log subsystem and | ||
353 | flushing is driven by log space and idling demands. The | ||
354 | xfsbufd no longer exists, so this syctl does nothing. | ||
355 | 353 | ||
356 | Due for removal in 3.14. | ||
357 | 354 | ||
358 | fs.xfs.age_buffer_centisecs (Min: 100 Default: 1500 Max: 720000) | 355 | Removed Sysctls |
359 | Dirty metadata is now tracked by the log subsystem and | 356 | =============== |
360 | flushing is driven by log space and idling demands. The | ||
361 | xfsbufd no longer exists, so this syctl does nothing. | ||
362 | 357 | ||
363 | Due for removal in 3.14. | 358 | Name Removed |
359 | ---- ------- | ||
360 | fs.xfs.xfsbufd_centisec v3.20 | ||
361 | fs.xfs.age_buffer_centisecs v3.20 | ||