diff options
Diffstat (limited to 'Documentation/filesystems')
-rw-r--r-- | Documentation/filesystems/Locking | 7 | ||||
-rw-r--r-- | Documentation/filesystems/omfs.txt | 106 | ||||
-rw-r--r-- | Documentation/filesystems/proc.txt | 48 | ||||
-rw-r--r-- | Documentation/filesystems/relay.txt | 10 | ||||
-rw-r--r-- | Documentation/filesystems/vfat.txt | 8 | ||||
-rw-r--r-- | Documentation/filesystems/vfs.txt | 6 |
6 files changed, 180 insertions, 5 deletions
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking index 8b22d7d8b991..680fb566b928 100644 --- a/Documentation/filesystems/Locking +++ b/Documentation/filesystems/Locking | |||
@@ -510,6 +510,7 @@ prototypes: | |||
510 | void (*close)(struct vm_area_struct*); | 510 | void (*close)(struct vm_area_struct*); |
511 | int (*fault)(struct vm_area_struct*, struct vm_fault *); | 511 | int (*fault)(struct vm_area_struct*, struct vm_fault *); |
512 | int (*page_mkwrite)(struct vm_area_struct *, struct page *); | 512 | int (*page_mkwrite)(struct vm_area_struct *, struct page *); |
513 | int (*access)(struct vm_area_struct *, unsigned long, void*, int, int); | ||
513 | 514 | ||
514 | locking rules: | 515 | locking rules: |
515 | BKL mmap_sem PageLocked(page) | 516 | BKL mmap_sem PageLocked(page) |
@@ -517,6 +518,7 @@ open: no yes | |||
517 | close: no yes | 518 | close: no yes |
518 | fault: no yes | 519 | fault: no yes |
519 | page_mkwrite: no yes no | 520 | page_mkwrite: no yes no |
521 | access: no yes | ||
520 | 522 | ||
521 | ->page_mkwrite() is called when a previously read-only page is | 523 | ->page_mkwrite() is called when a previously read-only page is |
522 | about to become writeable. The file system is responsible for | 524 | about to become writeable. The file system is responsible for |
@@ -525,6 +527,11 @@ taking to lock out truncate, the page range should be verified to be | |||
525 | within i_size. The page mapping should also be checked that it is not | 527 | within i_size. The page mapping should also be checked that it is not |
526 | NULL. | 528 | NULL. |
527 | 529 | ||
530 | ->access() is called when get_user_pages() fails in | ||
531 | acces_process_vm(), typically used to debug a process through | ||
532 | /proc/pid/mem or ptrace. This function is needed only for | ||
533 | VM_IO | VM_PFNMAP VMAs. | ||
534 | |||
528 | ================================================================================ | 535 | ================================================================================ |
529 | Dubious stuff | 536 | Dubious stuff |
530 | 537 | ||
diff --git a/Documentation/filesystems/omfs.txt b/Documentation/filesystems/omfs.txt new file mode 100644 index 000000000000..1d0d41ff5c65 --- /dev/null +++ b/Documentation/filesystems/omfs.txt | |||
@@ -0,0 +1,106 @@ | |||
1 | Optimized MPEG Filesystem (OMFS) | ||
2 | |||
3 | Overview | ||
4 | ======== | ||
5 | |||
6 | OMFS is a filesystem created by SonicBlue for use in the ReplayTV DVR | ||
7 | and Rio Karma MP3 player. The filesystem is extent-based, utilizing | ||
8 | block sizes from 2k to 8k, with hash-based directories. This | ||
9 | filesystem driver may be used to read and write disks from these | ||
10 | devices. | ||
11 | |||
12 | Note, it is not recommended that this FS be used in place of a general | ||
13 | filesystem for your own streaming media device. Native Linux filesystems | ||
14 | will likely perform better. | ||
15 | |||
16 | More information is available at: | ||
17 | |||
18 | http://linux-karma.sf.net/ | ||
19 | |||
20 | Various utilities, including mkomfs and omfsck, are included with | ||
21 | omfsprogs, available at: | ||
22 | |||
23 | http://bobcopeland.com/karma/ | ||
24 | |||
25 | Instructions are included in its README. | ||
26 | |||
27 | Options | ||
28 | ======= | ||
29 | |||
30 | OMFS supports the following mount-time options: | ||
31 | |||
32 | uid=n - make all files owned by specified user | ||
33 | gid=n - make all files owned by specified group | ||
34 | umask=xxx - set permission umask to xxx | ||
35 | fmask=xxx - set umask to xxx for files | ||
36 | dmask=xxx - set umask to xxx for directories | ||
37 | |||
38 | Disk format | ||
39 | =========== | ||
40 | |||
41 | OMFS discriminates between "sysblocks" and normal data blocks. The sysblock | ||
42 | group consists of super block information, file metadata, directory structures, | ||
43 | and extents. Each sysblock has a header containing CRCs of the entire | ||
44 | sysblock, and may be mirrored in successive blocks on the disk. A sysblock may | ||
45 | have a smaller size than a data block, but since they are both addressed by the | ||
46 | same 64-bit block number, any remaining space in the smaller sysblock is | ||
47 | unused. | ||
48 | |||
49 | Sysblock header information: | ||
50 | |||
51 | struct omfs_header { | ||
52 | __be64 h_self; /* FS block where this is located */ | ||
53 | __be32 h_body_size; /* size of useful data after header */ | ||
54 | __be16 h_crc; /* crc-ccitt of body_size bytes */ | ||
55 | char h_fill1[2]; | ||
56 | u8 h_version; /* version, always 1 */ | ||
57 | char h_type; /* OMFS_INODE_X */ | ||
58 | u8 h_magic; /* OMFS_IMAGIC */ | ||
59 | u8 h_check_xor; /* XOR of header bytes before this */ | ||
60 | __be32 h_fill2; | ||
61 | }; | ||
62 | |||
63 | Files and directories are both represented by omfs_inode: | ||
64 | |||
65 | struct omfs_inode { | ||
66 | struct omfs_header i_head; /* header */ | ||
67 | __be64 i_parent; /* parent containing this inode */ | ||
68 | __be64 i_sibling; /* next inode in hash bucket */ | ||
69 | __be64 i_ctime; /* ctime, in milliseconds */ | ||
70 | char i_fill1[35]; | ||
71 | char i_type; /* OMFS_[DIR,FILE] */ | ||
72 | __be32 i_fill2; | ||
73 | char i_fill3[64]; | ||
74 | char i_name[OMFS_NAMELEN]; /* filename */ | ||
75 | __be64 i_size; /* size of file, in bytes */ | ||
76 | }; | ||
77 | |||
78 | Directories in OMFS are implemented as a large hash table. Filenames are | ||
79 | hashed then prepended into the bucket list beginning at OMFS_DIR_START. | ||
80 | Lookup requires hashing the filename, then seeking across i_sibling pointers | ||
81 | until a match is found on i_name. Empty buckets are represented by block | ||
82 | pointers with all-1s (~0). | ||
83 | |||
84 | A file is an omfs_inode structure followed by an extent table beginning at | ||
85 | OMFS_EXTENT_START: | ||
86 | |||
87 | struct omfs_extent_entry { | ||
88 | __be64 e_cluster; /* start location of a set of blocks */ | ||
89 | __be64 e_blocks; /* number of blocks after e_cluster */ | ||
90 | }; | ||
91 | |||
92 | struct omfs_extent { | ||
93 | __be64 e_next; /* next extent table location */ | ||
94 | __be32 e_extent_count; /* total # extents in this table */ | ||
95 | __be32 e_fill; | ||
96 | struct omfs_extent_entry e_entry; /* start of extent entries */ | ||
97 | }; | ||
98 | |||
99 | Each extent holds the block offset followed by number of blocks allocated to | ||
100 | the extent. The final extent in each table is a terminator with e_cluster | ||
101 | being ~0 and e_blocks being ones'-complement of the total number of blocks | ||
102 | in the table. | ||
103 | |||
104 | If this table overflows, a continuation inode is written and pointed to by | ||
105 | e_next. These have a header but lack the rest of the inode structure. | ||
106 | |||
diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt index 7f268f327d75..64557821ee59 100644 --- a/Documentation/filesystems/proc.txt +++ b/Documentation/filesystems/proc.txt | |||
@@ -296,6 +296,7 @@ Table 1-4: Kernel info in /proc | |||
296 | uptime System uptime | 296 | uptime System uptime |
297 | version Kernel version | 297 | version Kernel version |
298 | video bttv info of video resources (2.4) | 298 | video bttv info of video resources (2.4) |
299 | vmallocinfo Show vmalloced areas | ||
299 | .............................................................................. | 300 | .............................................................................. |
300 | 301 | ||
301 | You can, for example, check which interrupts are currently in use and what | 302 | You can, for example, check which interrupts are currently in use and what |
@@ -557,6 +558,49 @@ VmallocTotal: total size of vmalloc memory area | |||
557 | VmallocUsed: amount of vmalloc area which is used | 558 | VmallocUsed: amount of vmalloc area which is used |
558 | VmallocChunk: largest contigious block of vmalloc area which is free | 559 | VmallocChunk: largest contigious block of vmalloc area which is free |
559 | 560 | ||
561 | .............................................................................. | ||
562 | |||
563 | vmallocinfo: | ||
564 | |||
565 | Provides information about vmalloced/vmaped areas. One line per area, | ||
566 | containing the virtual address range of the area, size in bytes, | ||
567 | caller information of the creator, and optional information depending | ||
568 | on the kind of area : | ||
569 | |||
570 | pages=nr number of pages | ||
571 | phys=addr if a physical address was specified | ||
572 | ioremap I/O mapping (ioremap() and friends) | ||
573 | vmalloc vmalloc() area | ||
574 | vmap vmap()ed pages | ||
575 | user VM_USERMAP area | ||
576 | vpages buffer for pages pointers was vmalloced (huge area) | ||
577 | N<node>=nr (Only on NUMA kernels) | ||
578 | Number of pages allocated on memory node <node> | ||
579 | |||
580 | > cat /proc/vmallocinfo | ||
581 | 0xffffc20000000000-0xffffc20000201000 2101248 alloc_large_system_hash+0x204 ... | ||
582 | /0x2c0 pages=512 vmalloc N0=128 N1=128 N2=128 N3=128 | ||
583 | 0xffffc20000201000-0xffffc20000302000 1052672 alloc_large_system_hash+0x204 ... | ||
584 | /0x2c0 pages=256 vmalloc N0=64 N1=64 N2=64 N3=64 | ||
585 | 0xffffc20000302000-0xffffc20000304000 8192 acpi_tb_verify_table+0x21/0x4f... | ||
586 | phys=7fee8000 ioremap | ||
587 | 0xffffc20000304000-0xffffc20000307000 12288 acpi_tb_verify_table+0x21/0x4f... | ||
588 | phys=7fee7000 ioremap | ||
589 | 0xffffc2000031d000-0xffffc2000031f000 8192 init_vdso_vars+0x112/0x210 | ||
590 | 0xffffc2000031f000-0xffffc2000032b000 49152 cramfs_uncompress_init+0x2e ... | ||
591 | /0x80 pages=11 vmalloc N0=3 N1=3 N2=2 N3=3 | ||
592 | 0xffffc2000033a000-0xffffc2000033d000 12288 sys_swapon+0x640/0xac0 ... | ||
593 | pages=2 vmalloc N1=2 | ||
594 | 0xffffc20000347000-0xffffc2000034c000 20480 xt_alloc_table_info+0xfe ... | ||
595 | /0x130 [x_tables] pages=4 vmalloc N0=4 | ||
596 | 0xffffffffa0000000-0xffffffffa000f000 61440 sys_init_module+0xc27/0x1d00 ... | ||
597 | pages=14 vmalloc N2=14 | ||
598 | 0xffffffffa000f000-0xffffffffa0014000 20480 sys_init_module+0xc27/0x1d00 ... | ||
599 | pages=4 vmalloc N1=4 | ||
600 | 0xffffffffa0014000-0xffffffffa0017000 12288 sys_init_module+0xc27/0x1d00 ... | ||
601 | pages=2 vmalloc N1=2 | ||
602 | 0xffffffffa0017000-0xffffffffa0022000 45056 sys_init_module+0xc27/0x1d00 ... | ||
603 | pages=10 vmalloc N0=10 | ||
560 | 604 | ||
561 | 1.3 IDE devices in /proc/ide | 605 | 1.3 IDE devices in /proc/ide |
562 | ---------------------------- | 606 | ---------------------------- |
@@ -887,7 +931,7 @@ group_prealloc max_to_scan mb_groups mb_history min_to_scan order2_req | |||
887 | stats stream_req | 931 | stats stream_req |
888 | 932 | ||
889 | mb_groups: | 933 | mb_groups: |
890 | This file gives the details of mutiblock allocator buddy cache of free blocks | 934 | This file gives the details of multiblock allocator buddy cache of free blocks |
891 | 935 | ||
892 | mb_history: | 936 | mb_history: |
893 | Multiblock allocation history. | 937 | Multiblock allocation history. |
@@ -1430,7 +1474,7 @@ used because pages_free(1355) is smaller than watermark + protection[2] | |||
1430 | normal page requirement. If requirement is DMA zone(index=0), protection[0] | 1474 | normal page requirement. If requirement is DMA zone(index=0), protection[0] |
1431 | (=0) is used. | 1475 | (=0) is used. |
1432 | 1476 | ||
1433 | zone[i]'s protection[j] is calculated by following exprssion. | 1477 | zone[i]'s protection[j] is calculated by following expression. |
1434 | 1478 | ||
1435 | (i < j): | 1479 | (i < j): |
1436 | zone[i]->protection[j] | 1480 | zone[i]->protection[j] |
diff --git a/Documentation/filesystems/relay.txt b/Documentation/filesystems/relay.txt index 094f2d2f38b1..510b722667ac 100644 --- a/Documentation/filesystems/relay.txt +++ b/Documentation/filesystems/relay.txt | |||
@@ -294,6 +294,16 @@ user-defined data with a channel, and is immediately available | |||
294 | (including in create_buf_file()) via chan->private_data or | 294 | (including in create_buf_file()) via chan->private_data or |
295 | buf->chan->private_data. | 295 | buf->chan->private_data. |
296 | 296 | ||
297 | Buffer-only channels | ||
298 | -------------------- | ||
299 | |||
300 | These channels have no files associated and can be created with | ||
301 | relay_open(NULL, NULL, ...). Such channels are useful in scenarios such | ||
302 | as when doing early tracing in the kernel, before the VFS is up. In these | ||
303 | cases, one may open a buffer-only channel and then call | ||
304 | relay_late_setup_files() when the kernel is ready to handle files, | ||
305 | to expose the buffered data to the userspace. | ||
306 | |||
297 | Channel 'modes' | 307 | Channel 'modes' |
298 | --------------- | 308 | --------------- |
299 | 309 | ||
diff --git a/Documentation/filesystems/vfat.txt b/Documentation/filesystems/vfat.txt index 2d5e1e582e13..bbac4f1d9056 100644 --- a/Documentation/filesystems/vfat.txt +++ b/Documentation/filesystems/vfat.txt | |||
@@ -96,6 +96,14 @@ shortname=lower|win95|winnt|mixed | |||
96 | emulate the Windows 95 rule for create. | 96 | emulate the Windows 95 rule for create. |
97 | Default setting is `lower'. | 97 | Default setting is `lower'. |
98 | 98 | ||
99 | tz=UTC -- Interpret timestamps as UTC rather than local time. | ||
100 | This option disables the conversion of timestamps | ||
101 | between local time (as used by Windows on FAT) and UTC | ||
102 | (which Linux uses internally). This is particuluarly | ||
103 | useful when mounting devices (like digital cameras) | ||
104 | that are set to UTC in order to avoid the pitfalls of | ||
105 | local time. | ||
106 | |||
99 | <bool>: 0,1,yes,no,true,false | 107 | <bool>: 0,1,yes,no,true,false |
100 | 108 | ||
101 | TODO | 109 | TODO |
diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt index b7522c6cbae3..c4d348dabe94 100644 --- a/Documentation/filesystems/vfs.txt +++ b/Documentation/filesystems/vfs.txt | |||
@@ -143,7 +143,7 @@ struct file_system_type { | |||
143 | 143 | ||
144 | The get_sb() method has the following arguments: | 144 | The get_sb() method has the following arguments: |
145 | 145 | ||
146 | struct file_system_type *fs_type: decribes the filesystem, partly initialized | 146 | struct file_system_type *fs_type: describes the filesystem, partly initialized |
147 | by the specific filesystem code | 147 | by the specific filesystem code |
148 | 148 | ||
149 | int flags: mount flags | 149 | int flags: mount flags |
@@ -895,9 +895,9 @@ struct dentry_operations { | |||
895 | iput() yourself | 895 | iput() yourself |
896 | 896 | ||
897 | d_dname: called when the pathname of a dentry should be generated. | 897 | d_dname: called when the pathname of a dentry should be generated. |
898 | Usefull for some pseudo filesystems (sockfs, pipefs, ...) to delay | 898 | Useful for some pseudo filesystems (sockfs, pipefs, ...) to delay |
899 | pathname generation. (Instead of doing it when dentry is created, | 899 | pathname generation. (Instead of doing it when dentry is created, |
900 | its done only when the path is needed.). Real filesystems probably | 900 | it's done only when the path is needed.). Real filesystems probably |
901 | dont want to use it, because their dentries are present in global | 901 | dont want to use it, because their dentries are present in global |
902 | dcache hash, so their hash should be an invariant. As no lock is | 902 | dcache hash, so their hash should be an invariant. As no lock is |
903 | held, d_dname() should not try to modify the dentry itself, unless | 903 | held, d_dname() should not try to modify the dentry itself, unless |