aboutsummaryrefslogtreecommitdiffstats
path: root/include/linux
diff options
context:
space:
mode:
authorAmit Arora <aarora@in.ibm.com>2007-07-17 21:42:44 -0400
committerTheodore Ts'o <tytso@mit.edu>2007-07-17 21:42:44 -0400
commit97ac73506c0ba93f30239bb57b4cfc5d73e68a62 (patch)
tree4d02848d6c792a70b413deadcaffd7bf8c8d61de /include/linux
parentcb32da0416b823b7f4b65e7e85d6cba16ca4d1e1 (diff)
sys_fallocate() implementation on i386, x86_64 and powerpc
fallocate() is a new system call being proposed here which will allow applications to preallocate space to any file(s) in a file system. Each file system implementation that wants to use this feature will need to support an inode operation called ->fallocate(). Applications can use this feature to avoid fragmentation to certain level and thus get faster access speed. With preallocation, applications also get a guarantee of space for particular file(s) - even if later the the system becomes full. Currently, glibc provides an interface called posix_fallocate() which can be used for similar cause. Though this has the advantage of working on all file systems, but it is quite slow (since it writes zeroes to each block that has to be preallocated). Without a doubt, file systems can do this more efficiently within the kernel, by implementing the proposed fallocate() system call. It is expected that posix_fallocate() will be modified to call this new system call first and incase the kernel/filesystem does not implement it, it should fall back to the current implementation of writing zeroes to the new blocks. ToDos: 1. Implementation on other architectures (other than i386, x86_64, and ppc). Patches for s390(x) and ia64 are already available from previous posts, but it was decided that they should be added later once fallocate is in the mainline. Hence not including those patches in this take. 2. Changes to glibc, a) to support fallocate() system call b) to make posix_fallocate() and posix_fallocate64() call fallocate() Signed-off-by: Amit Arora <aarora@in.ibm.com>
Diffstat (limited to 'include/linux')
-rw-r--r--include/linux/falloc.h6
-rw-r--r--include/linux/fs.h2
-rw-r--r--include/linux/syscalls.h1
3 files changed, 9 insertions, 0 deletions
diff --git a/include/linux/falloc.h b/include/linux/falloc.h
new file mode 100644
index 000000000000..8e912ab6a072
--- /dev/null
+++ b/include/linux/falloc.h
@@ -0,0 +1,6 @@
1#ifndef _FALLOC_H_
2#define _FALLOC_H_
3
4#define FALLOC_FL_KEEP_SIZE 0x01 /* default is extend size */
5
6#endif /* _FALLOC_H_ */
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 98205f680476..0b806c5e32eb 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1147,6 +1147,8 @@ struct inode_operations {
1147 ssize_t (*listxattr) (struct dentry *, char *, size_t); 1147 ssize_t (*listxattr) (struct dentry *, char *, size_t);
1148 int (*removexattr) (struct dentry *, const char *); 1148 int (*removexattr) (struct dentry *, const char *);
1149 void (*truncate_range)(struct inode *, loff_t, loff_t); 1149 void (*truncate_range)(struct inode *, loff_t, loff_t);
1150 long (*fallocate)(struct inode *inode, int mode, loff_t offset,
1151 loff_t len);
1150}; 1152};
1151 1153
1152struct seq_file; 1154struct seq_file;
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 83d0ec11235e..7a8b1e3322e0 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -610,6 +610,7 @@ asmlinkage long sys_signalfd(int ufd, sigset_t __user *user_mask, size_t sizemas
610asmlinkage long sys_timerfd(int ufd, int clockid, int flags, 610asmlinkage long sys_timerfd(int ufd, int clockid, int flags,
611 const struct itimerspec __user *utmr); 611 const struct itimerspec __user *utmr);
612asmlinkage long sys_eventfd(unsigned int count); 612asmlinkage long sys_eventfd(unsigned int count);
613asmlinkage long sys_fallocate(int fd, int mode, loff_t offset, loff_t len);
613 614
614int kernel_execve(const char *filename, char *const argv[], char *const envp[]); 615int kernel_execve(const char *filename, char *const argv[], char *const envp[]);
615 616