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authorAndrew Morton2006-03-31 04:30:42 -0600
committerLinus Torvalds2006-03-31 14:18:54 -0600
commitf79e2abb9bd452d97295f34376dedbec9686b986 (patch)
tree56b9998caa11983556e842fb9a8143d86d765fa3
parentd6dfd1310d3562698fd7c3c086f6c239f96394ac (diff)
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[PATCH] sys_sync_file_range()
Remove the recently-added LINUX_FADV_ASYNC_WRITE and LINUX_FADV_WRITE_WAIT fadvise() additions, do it in a new sys_sync_file_range() syscall instead. Reasons: - It's more flexible. Things which would require two or three syscalls with fadvise() can be done in a single syscall. - Using fadvise() in this manner is something not covered by POSIX. The patch wires up the syscall for x86. The sycall is implemented in the new fs/sync.c. The intention is that we can move sys_fsync(), sys_fdatasync() and perhaps sys_sync() into there later. Documentation for the syscall is in fs/sync.c. A test app (sync_file_range.c) is in http://www.zip.com.au/~akpm/linux/patches/stuff/ext3-tools.tar.gz. The available-to-GPL-modules do_sync_file_range() is for knfsd: "A COMMIT can say NFS_DATA_SYNC or NFS_FILE_SYNC. I can skip the ->fsync call for NFS_DATA_SYNC which is hopefully the more common." Note: the `async' writeout mode SYNC_FILE_RANGE_WRITE will turn synchronous if the queue is congested. This is trivial to fix: add a new flag bit, set wbc->nonblocking. But I'm not sure that we want to expose implementation details down to that level. Note: it's notable that we can sync an fd which wasn't opened for writing. Same with fsync() and fdatasync()). Note: the code takes some care to handle attempts to sync file contents outside the 16TB offset on 32-bit machines. It makes such attempts appear to succeed, for best 32-bit/64-bit compatibility. Perhaps it should make such requests fail... Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Michael Kerrisk <mtk-manpages@gmx.net> Cc: Ulrich Drepper <drepper@redhat.com> Cc: Neil Brown <neilb@cse.unsw.edu.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--arch/i386/kernel/syscall_table.S1
-rw-r--r--fs/Makefile2
-rw-r--r--fs/sync.c164
-rw-r--r--include/asm-i386/unistd.h3
-rw-r--r--include/linux/fadvise.h6
-rw-r--r--include/linux/fs.h7
-rw-r--r--include/linux/syscalls.h2
-rw-r--r--mm/fadvise.c20
8 files changed, 177 insertions, 28 deletions
diff --git a/arch/i386/kernel/syscall_table.S b/arch/i386/kernel/syscall_table.S
index ce3ef4fa055..4f58b9c0efe 100644
--- a/arch/i386/kernel/syscall_table.S
+++ b/arch/i386/kernel/syscall_table.S
@@ -313,3 +313,4 @@ ENTRY(sys_call_table)
313 .long sys_set_robust_list 313 .long sys_set_robust_list
314 .long sys_get_robust_list 314 .long sys_get_robust_list
315 .long sys_splice 315 .long sys_splice
316 .long sys_sync_file_range
diff --git a/fs/Makefile b/fs/Makefile
index f3a4f707717..83bf478e786 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -10,7 +10,7 @@ obj-y := open.o read_write.o file_table.o buffer.o bio.o super.o \
10 ioctl.o readdir.o select.o fifo.o locks.o dcache.o inode.o \ 10 ioctl.o readdir.o select.o fifo.o locks.o dcache.o inode.o \
11 attr.o bad_inode.o file.o filesystems.o namespace.o aio.o \ 11 attr.o bad_inode.o file.o filesystems.o namespace.o aio.o \
12 seq_file.o xattr.o libfs.o fs-writeback.o mpage.o direct-io.o \ 12 seq_file.o xattr.o libfs.o fs-writeback.o mpage.o direct-io.o \
13 ioprio.o pnode.o drop_caches.o splice.o 13 ioprio.o pnode.o drop_caches.o splice.o sync.o
14 14
15obj-$(CONFIG_INOTIFY) += inotify.o 15obj-$(CONFIG_INOTIFY) += inotify.o
16obj-$(CONFIG_EPOLL) += eventpoll.o 16obj-$(CONFIG_EPOLL) += eventpoll.o
diff --git a/fs/sync.c b/fs/sync.c
new file mode 100644
index 00000000000..8616006d209
--- /dev/null
+++ b/fs/sync.c
@@ -0,0 +1,164 @@
1/*
2 * High-level sync()-related operations
3 */
4
5#include <linux/kernel.h>
6#include <linux/file.h>
7#include <linux/fs.h>
8#include <linux/module.h>
9#include <linux/writeback.h>
10#include <linux/syscalls.h>
11#include <linux/linkage.h>
12#include <linux/pagemap.h>
13
14#define VALID_FLAGS (SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE| \
15 SYNC_FILE_RANGE_WAIT_AFTER)
16
17/*
18 * sys_sync_file_range() permits finely controlled syncing over a segment of
19 * a file in the range offset .. (offset+nbytes-1) inclusive. If nbytes is
20 * zero then sys_sync_file_range() will operate from offset out to EOF.
21 *
22 * The flag bits are:
23 *
24 * SYNC_FILE_RANGE_WAIT_BEFORE: wait upon writeout of all pages in the range
25 * before performing the write.
26 *
27 * SYNC_FILE_RANGE_WRITE: initiate writeout of all those dirty pages in the
28 * range which are not presently under writeback.
29 *
30 * SYNC_FILE_RANGE_WAIT_AFTER: wait upon writeout of all pages in the range
31 * after performing the write.
32 *
33 * Useful combinations of the flag bits are:
34 *
35 * SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE: ensures that all pages
36 * in the range which were dirty on entry to sys_sync_file_range() are placed
37 * under writeout. This is a start-write-for-data-integrity operation.
38 *
39 * SYNC_FILE_RANGE_WRITE: start writeout of all dirty pages in the range which
40 * are not presently under writeout. This is an asynchronous flush-to-disk
41 * operation. Not suitable for data integrity operations.
42 *
43 * SYNC_FILE_RANGE_WAIT_BEFORE (or SYNC_FILE_RANGE_WAIT_AFTER): wait for
44 * completion of writeout of all pages in the range. This will be used after an
45 * earlier SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE operation to wait
46 * for that operation to complete and to return the result.
47 *
48 * SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE|SYNC_FILE_RANGE_WAIT_AFTER:
49 * a traditional sync() operation. This is a write-for-data-integrity operation
50 * which will ensure that all pages in the range which were dirty on entry to
51 * sys_sync_file_range() are committed to disk.
52 *
53 *
54 * SYNC_FILE_RANGE_WAIT_BEFORE and SYNC_FILE_RANGE_WAIT_AFTER will detect any
55 * I/O errors or ENOSPC conditions and will return those to the caller, after
56 * clearing the EIO and ENOSPC flags in the address_space.
57 *
58 * It should be noted that none of these operations write out the file's
59 * metadata. So unless the application is strictly performing overwrites of
60 * already-instantiated disk blocks, there are no guarantees here that the data
61 * will be available after a crash.
62 */
63asmlinkage long sys_sync_file_range(int fd, loff_t offset, loff_t nbytes,
64 int flags)
65{
66 int ret;
67 struct file *file;
68 loff_t endbyte; /* inclusive */
69 int fput_needed;
70 umode_t i_mode;
71
72 ret = -EINVAL;
73 if (flags & ~VALID_FLAGS)
74 goto out;
75
76 endbyte = offset + nbytes;
77
78 if ((s64)offset < 0)
79 goto out;
80 if ((s64)endbyte < 0)
81 goto out;
82 if (endbyte < offset)
83 goto out;
84
85 if (sizeof(pgoff_t) == 4) {
86 if (offset >= (0x100000000ULL << PAGE_CACHE_SHIFT)) {
87 /*
88 * The range starts outside a 32 bit machine's
89 * pagecache addressing capabilities. Let it "succeed"
90 */
91 ret = 0;
92 goto out;
93 }
94 if (endbyte >= (0x100000000ULL << PAGE_CACHE_SHIFT)) {
95 /*
96 * Out to EOF
97 */
98 nbytes = 0;
99 }
100 }
101
102 if (nbytes == 0)
103 endbyte = -1;
104 else
105 endbyte--; /* inclusive */
106
107 ret = -EBADF;
108 file = fget_light(fd, &fput_needed);
109 if (!file)
110 goto out;
111
112 i_mode = file->f_dentry->d_inode->i_mode;
113 ret = -ESPIPE;
114 if (!S_ISREG(i_mode) && !S_ISBLK(i_mode) && !S_ISDIR(i_mode) &&
115 !S_ISLNK(i_mode))
116 goto out_put;
117
118 ret = do_sync_file_range(file, offset, endbyte, flags);
119out_put:
120 fput_light(file, fput_needed);
121out:
122 return ret;
123}
124
125/*
126 * `endbyte' is inclusive
127 */
128int do_sync_file_range(struct file *file, loff_t offset, loff_t endbyte,
129 int flags)
130{
131 int ret;
132 struct address_space *mapping;
133
134 mapping = file->f_mapping;
135 if (!mapping) {
136 ret = -EINVAL;
137 goto out;
138 }
139
140 ret = 0;
141 if (flags & SYNC_FILE_RANGE_WAIT_BEFORE) {
142 ret = wait_on_page_writeback_range(mapping,
143 offset >> PAGE_CACHE_SHIFT,
144 endbyte >> PAGE_CACHE_SHIFT);
145 if (ret < 0)
146 goto out;
147 }
148
149 if (flags & SYNC_FILE_RANGE_WRITE) {
150 ret = __filemap_fdatawrite_range(mapping, offset, endbyte,
151 WB_SYNC_NONE);
152 if (ret < 0)
153 goto out;
154 }
155
156 if (flags & SYNC_FILE_RANGE_WAIT_AFTER) {
157 ret = wait_on_page_writeback_range(mapping,
158 offset >> PAGE_CACHE_SHIFT,
159 endbyte >> PAGE_CACHE_SHIFT);
160 }
161out:
162 return ret;
163}
164EXPORT_SYMBOL_GPL(do_sync_file_range);
diff --git a/include/asm-i386/unistd.h b/include/asm-i386/unistd.h
index 789e9bdd0a4..2e7f3e257fd 100644
--- a/include/asm-i386/unistd.h
+++ b/include/asm-i386/unistd.h
@@ -319,8 +319,9 @@
319#define __NR_set_robust_list 311 319#define __NR_set_robust_list 311
320#define __NR_get_robust_list 312 320#define __NR_get_robust_list 312
321#define __NR_sys_splice 313 321#define __NR_sys_splice 313
322#define __NR_sys_sync_file_range 314
322 323
323#define NR_syscalls 314 324#define NR_syscalls 315
324 325
325/* 326/*
326 * user-visible error numbers are in the range -1 - -128: see 327 * user-visible error numbers are in the range -1 - -128: see
diff --git a/include/linux/fadvise.h b/include/linux/fadvise.h
index b2913bba35d..e8e747139b9 100644
--- a/include/linux/fadvise.h
+++ b/include/linux/fadvise.h
@@ -18,10 +18,4 @@
18#define POSIX_FADV_NOREUSE 5 /* Data will be accessed once. */ 18#define POSIX_FADV_NOREUSE 5 /* Data will be accessed once. */
19#endif 19#endif
20 20
21/*
22 * Linux-specific fadvise() extensions:
23 */
24#define LINUX_FADV_ASYNC_WRITE 32 /* Start writeout on range */
25#define LINUX_FADV_WRITE_WAIT 33 /* Wait upon writeout to range */
26
27#endif /* FADVISE_H_INCLUDED */ 21#endif /* FADVISE_H_INCLUDED */
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 20a7afd4590..4ed7e602d70 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -757,6 +757,13 @@ extern void send_sigio(struct fown_struct *fown, int fd, int band);
757extern int fcntl_setlease(unsigned int fd, struct file *filp, long arg); 757extern int fcntl_setlease(unsigned int fd, struct file *filp, long arg);
758extern int fcntl_getlease(struct file *filp); 758extern int fcntl_getlease(struct file *filp);
759 759
760/* fs/sync.c */
761#define SYNC_FILE_RANGE_WAIT_BEFORE 1
762#define SYNC_FILE_RANGE_WRITE 2
763#define SYNC_FILE_RANGE_WAIT_AFTER 4
764extern int do_sync_file_range(struct file *file, loff_t offset, loff_t endbyte,
765 int flags);
766
760/* fs/locks.c */ 767/* fs/locks.c */
761extern void locks_init_lock(struct file_lock *); 768extern void locks_init_lock(struct file_lock *);
762extern void locks_copy_lock(struct file_lock *, struct file_lock *); 769extern void locks_copy_lock(struct file_lock *, struct file_lock *);
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index e78ffc7d5b5..5717147596b 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -571,5 +571,7 @@ asmlinkage long compat_sys_openat(unsigned int dfd, const char __user *filename,
571asmlinkage long sys_unshare(unsigned long unshare_flags); 571asmlinkage long sys_unshare(unsigned long unshare_flags);
572asmlinkage long sys_splice(int fdin, int fdout, size_t len, 572asmlinkage long sys_splice(int fdin, int fdout, size_t len,
573 unsigned int flags); 573 unsigned int flags);
574asmlinkage long sys_sync_file_range(int fd, loff_t offset, loff_t nbytes,
575 int flags);
574 576
575#endif 577#endif
diff --git a/mm/fadvise.c b/mm/fadvise.c
index 907c39257ca..0a03357a1f8 100644
--- a/mm/fadvise.c
+++ b/mm/fadvise.c
@@ -35,17 +35,6 @@
35 * 35 *
36 * LINUX_FADV_ASYNC_WRITE: push some or all of the dirty pages at the disk. 36 * LINUX_FADV_ASYNC_WRITE: push some or all of the dirty pages at the disk.
37 * 37 *
38 * LINUX_FADV_WRITE_WAIT, LINUX_FADV_ASYNC_WRITE: push all of the currently
39 * dirty pages at the disk.
40 *
41 * LINUX_FADV_WRITE_WAIT, LINUX_FADV_ASYNC_WRITE, LINUX_FADV_WRITE_WAIT: push
42 * all of the currently dirty pages at the disk, wait until they have been
43 * written.
44 *
45 * It should be noted that none of these operations write out the file's
46 * metadata. So unless the application is strictly performing overwrites of
47 * already-instantiated disk blocks, there are no guarantees here that the data
48 * will be available after a crash.
49 */ 38 */
50asmlinkage long sys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice) 39asmlinkage long sys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice)
51{ 40{
@@ -129,15 +118,6 @@ asmlinkage long sys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice)
129 invalidate_mapping_pages(mapping, start_index, 118 invalidate_mapping_pages(mapping, start_index,
130 end_index); 119 end_index);
131 break; 120 break;
132 case LINUX_FADV_ASYNC_WRITE:
133 ret = __filemap_fdatawrite_range(mapping, offset, endbyte,
134 WB_SYNC_NONE);
135 break;
136 case LINUX_FADV_WRITE_WAIT:
137 ret = wait_on_page_writeback_range(mapping,
138 offset >> PAGE_CACHE_SHIFT,
139 endbyte >> PAGE_CACHE_SHIFT);
140 break;
141 default: 121 default:
142 ret = -EINVAL; 122 ret = -EINVAL;
143 } 123 }