From 97ac73506c0ba93f30239bb57b4cfc5d73e68a62 Mon Sep 17 00:00:00 2001 From: Amit Arora Date: Tue, 17 Jul 2007 21:42:44 -0400 Subject: [PATCH] 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 --- arch/i386/kernel/syscall_table.S | 1 + arch/powerpc/kernel/sys_ppc32.c | 7 ++++ arch/x86_64/ia32/ia32entry.S | 1 + arch/x86_64/ia32/sys_ia32.c | 8 +++++ fs/open.c | 59 ++++++++++++++++++++++++++++++++ include/asm-i386/unistd.h | 3 +- include/asm-powerpc/systbl.h | 1 + include/asm-powerpc/unistd.h | 3 +- include/asm-x86_64/unistd.h | 2 ++ include/linux/falloc.h | 6 ++++ include/linux/fs.h | 2 ++ include/linux/syscalls.h | 1 + 12 files changed, 92 insertions(+), 2 deletions(-) create mode 100644 include/linux/falloc.h diff --git a/arch/i386/kernel/syscall_table.S b/arch/i386/kernel/syscall_table.S index bf6adce522..8344c70adf 100644 --- a/arch/i386/kernel/syscall_table.S +++ b/arch/i386/kernel/syscall_table.S @@ -323,3 +323,4 @@ ENTRY(sys_call_table) .long sys_signalfd .long sys_timerfd .long sys_eventfd + .long sys_fallocate diff --git a/arch/powerpc/kernel/sys_ppc32.c b/arch/powerpc/kernel/sys_ppc32.c index b42cbf1e2d..bd85b5fd08 100644 --- a/arch/powerpc/kernel/sys_ppc32.c +++ b/arch/powerpc/kernel/sys_ppc32.c @@ -773,6 +773,13 @@ asmlinkage int compat_sys_truncate64(const char __user * path, u32 reg4, return sys_truncate(path, (high << 32) | low); } +asmlinkage long compat_sys_fallocate(int fd, int mode, u32 offhi, u32 offlo, + u32 lenhi, u32 lenlo) +{ + return sys_fallocate(fd, mode, ((loff_t)offhi << 32) | offlo, + ((loff_t)lenhi << 32) | lenlo); +} + asmlinkage int compat_sys_ftruncate64(unsigned int fd, u32 reg4, unsigned long high, unsigned long low) { diff --git a/arch/x86_64/ia32/ia32entry.S b/arch/x86_64/ia32/ia32entry.S index 782dea8194..3f66e970d8 100644 --- a/arch/x86_64/ia32/ia32entry.S +++ b/arch/x86_64/ia32/ia32entry.S @@ -719,4 +719,5 @@ ia32_sys_call_table: .quad compat_sys_signalfd .quad compat_sys_timerfd .quad sys_eventfd + .quad sys32_fallocate ia32_syscall_end: diff --git a/arch/x86_64/ia32/sys_ia32.c b/arch/x86_64/ia32/sys_ia32.c index 99a78a3cce..bee96d6144 100644 --- a/arch/x86_64/ia32/sys_ia32.c +++ b/arch/x86_64/ia32/sys_ia32.c @@ -879,3 +879,11 @@ asmlinkage long sys32_fadvise64(int fd, unsigned offset_lo, unsigned offset_hi, return sys_fadvise64_64(fd, ((u64)offset_hi << 32) | offset_lo, len, advice); } + +asmlinkage long sys32_fallocate(int fd, int mode, unsigned offset_lo, + unsigned offset_hi, unsigned len_lo, + unsigned len_hi) +{ + return sys_fallocate(fd, mode, ((u64)offset_hi << 32) | offset_lo, + ((u64)len_hi << 32) | len_lo); +} diff --git a/fs/open.c b/fs/open.c index be6a457f42..a6b054edac 100644 --- a/fs/open.c +++ b/fs/open.c @@ -26,6 +26,7 @@ #include #include #include +#include int vfs_statfs(struct dentry *dentry, struct kstatfs *buf) { @@ -352,6 +353,64 @@ asmlinkage long sys_ftruncate64(unsigned int fd, loff_t length) } #endif +asmlinkage long sys_fallocate(int fd, int mode, loff_t offset, loff_t len) +{ + struct file *file; + struct inode *inode; + long ret = -EINVAL; + + if (offset < 0 || len <= 0) + goto out; + + /* Return error if mode is not supported */ + ret = -EOPNOTSUPP; + if (mode && !(mode & FALLOC_FL_KEEP_SIZE)) + goto out; + + ret = -EBADF; + file = fget(fd); + if (!file) + goto out; + if (!(file->f_mode & FMODE_WRITE)) + goto out_fput; + /* + * Revalidate the write permissions, in case security policy has + * changed since the files were opened. + */ + ret = security_file_permission(file, MAY_WRITE); + if (ret) + goto out_fput; + + inode = file->f_path.dentry->d_inode; + + ret = -ESPIPE; + if (S_ISFIFO(inode->i_mode)) + goto out_fput; + + ret = -ENODEV; + /* + * Let individual file system decide if it supports preallocation + * for directories or not. + */ + if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode)) + goto out_fput; + + ret = -EFBIG; + /* Check for wrap through zero too */ + if (((offset + len) > inode->i_sb->s_maxbytes) || ((offset + len) < 0)) + goto out_fput; + + if (inode->i_op && inode->i_op->fallocate) + ret = inode->i_op->fallocate(inode, mode, offset, len); + else + ret = -ENOSYS; + +out_fput: + fput(file); +out: + return ret; +} + /* * access() needs to use the real uid/gid, not the effective uid/gid. * We do this by temporarily clearing all FS-related capabilities and diff --git a/include/asm-i386/unistd.h b/include/asm-i386/unistd.h index e84ace1ec8..9b15545eb9 100644 --- a/include/asm-i386/unistd.h +++ b/include/asm-i386/unistd.h @@ -329,10 +329,11 @@ #define __NR_signalfd 321 #define __NR_timerfd 322 #define __NR_eventfd 323 +#define __NR_fallocate 324 #ifdef __KERNEL__ -#define NR_syscalls 324 +#define NR_syscalls 325 #define __ARCH_WANT_IPC_PARSE_VERSION #define __ARCH_WANT_OLD_READDIR diff --git a/include/asm-powerpc/systbl.h b/include/asm-powerpc/systbl.h index 1cc3f9cb6f..cc6d872282 100644 --- a/include/asm-powerpc/systbl.h +++ b/include/asm-powerpc/systbl.h @@ -308,6 +308,7 @@ COMPAT_SYS_SPU(move_pages) SYSCALL_SPU(getcpu) COMPAT_SYS(epoll_pwait) COMPAT_SYS_SPU(utimensat) +COMPAT_SYS(fallocate) COMPAT_SYS_SPU(signalfd) COMPAT_SYS_SPU(timerfd) SYSCALL_SPU(eventfd) diff --git a/include/asm-powerpc/unistd.h b/include/asm-powerpc/unistd.h index f71c6061f1..97d82b6a94 100644 --- a/include/asm-powerpc/unistd.h +++ b/include/asm-powerpc/unistd.h @@ -331,10 +331,11 @@ #define __NR_timerfd 306 #define __NR_eventfd 307 #define __NR_sync_file_range2 308 +#define __NR_fallocate 309 #ifdef __KERNEL__ -#define __NR_syscalls 309 +#define __NR_syscalls 310 #define __NR__exit __NR_exit #define NR_syscalls __NR_syscalls diff --git a/include/asm-x86_64/unistd.h b/include/asm-x86_64/unistd.h index 8696f8ad40..fc4e73f5f1 100644 --- a/include/asm-x86_64/unistd.h +++ b/include/asm-x86_64/unistd.h @@ -630,6 +630,8 @@ __SYSCALL(__NR_signalfd, sys_signalfd) __SYSCALL(__NR_timerfd, sys_timerfd) #define __NR_eventfd 284 __SYSCALL(__NR_eventfd, sys_eventfd) +#define __NR_fallocate 285 +__SYSCALL(__NR_fallocate, sys_fallocate) #ifndef __NO_STUBS #define __ARCH_WANT_OLD_READDIR diff --git a/include/linux/falloc.h b/include/linux/falloc.h new file mode 100644 index 0000000000..8e912ab6a0 --- /dev/null +++ b/include/linux/falloc.h @@ -0,0 +1,6 @@ +#ifndef _FALLOC_H_ +#define _FALLOC_H_ + +#define FALLOC_FL_KEEP_SIZE 0x01 /* default is extend size */ + +#endif /* _FALLOC_H_ */ diff --git a/include/linux/fs.h b/include/linux/fs.h index 98205f6804..0b806c5e32 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1147,6 +1147,8 @@ struct inode_operations { ssize_t (*listxattr) (struct dentry *, char *, size_t); int (*removexattr) (struct dentry *, const char *); void (*truncate_range)(struct inode *, loff_t, loff_t); + long (*fallocate)(struct inode *inode, int mode, loff_t offset, + loff_t len); }; struct seq_file; diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index 83d0ec1123..7a8b1e3322 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 asmlinkage long sys_timerfd(int ufd, int clockid, int flags, const struct itimerspec __user *utmr); asmlinkage long sys_eventfd(unsigned int count); +asmlinkage long sys_fallocate(int fd, int mode, loff_t offset, loff_t len); int kernel_execve(const char *filename, char *const argv[], char *const envp[]); -- 2.39.5