Merge branch 'for-2.6.34' of git://linux-nfs.org/~bfields/linux
[linux-2.6.git] / fs / read_write.c
index bcb0ef2..b7f4a1f 100644 (file)
@@ -15,6 +15,7 @@
 #include <linux/module.h>
 #include <linux/syscalls.h>
 #include <linux/pagemap.h>
+#include <linux/splice.h>
 #include "read_write.h"
 
 #include <asm/uaccess.h>
@@ -25,62 +26,76 @@ const struct file_operations generic_ro_fops = {
        .read           = do_sync_read,
        .aio_read       = generic_file_aio_read,
        .mmap           = generic_file_readonly_mmap,
-       .sendfile       = generic_file_sendfile,
+       .splice_read    = generic_file_splice_read,
 };
 
 EXPORT_SYMBOL(generic_ro_fops);
 
-loff_t generic_file_llseek(struct file *file, loff_t offset, int origin)
+/**
+ * generic_file_llseek_unlocked - lockless generic llseek implementation
+ * @file:      file structure to seek on
+ * @offset:    file offset to seek to
+ * @origin:    type of seek
+ *
+ * Updates the file offset to the value specified by @offset and @origin.
+ * Locking must be provided by the caller.
+ */
+loff_t
+generic_file_llseek_unlocked(struct file *file, loff_t offset, int origin)
 {
-       long long retval;
        struct inode *inode = file->f_mapping->host;
 
-       mutex_lock(&inode->i_mutex);
        switch (origin) {
-               case 2:
-                       offset += inode->i_size;
-                       break;
-               case 1:
-                       offset += file->f_pos;
-       }
-       retval = -EINVAL;
-       if (offset>=0 && offset<=inode->i_sb->s_maxbytes) {
-               if (offset != file->f_pos) {
-                       file->f_pos = offset;
-                       file->f_version = 0;
-               }
-               retval = offset;
+       case SEEK_END:
+               offset += inode->i_size;
+               break;
+       case SEEK_CUR:
+               /*
+                * Here we special-case the lseek(fd, 0, SEEK_CUR)
+                * position-querying operation.  Avoid rewriting the "same"
+                * f_pos value back to the file because a concurrent read(),
+                * write() or lseek() might have altered it
+                */
+               if (offset == 0)
+                       return file->f_pos;
+               offset += file->f_pos;
+               break;
+       }
+
+       if (offset < 0 || offset > inode->i_sb->s_maxbytes)
+               return -EINVAL;
+
+       /* Special lock needed here? */
+       if (offset != file->f_pos) {
+               file->f_pos = offset;
+               file->f_version = 0;
        }
-       mutex_unlock(&inode->i_mutex);
-       return retval;
-}
 
-EXPORT_SYMBOL(generic_file_llseek);
+       return offset;
+}
+EXPORT_SYMBOL(generic_file_llseek_unlocked);
 
-loff_t remote_llseek(struct file *file, loff_t offset, int origin)
+/**
+ * generic_file_llseek - generic llseek implementation for regular files
+ * @file:      file structure to seek on
+ * @offset:    file offset to seek to
+ * @origin:    type of seek
+ *
+ * This is a generic implemenation of ->llseek useable for all normal local
+ * filesystems.  It just updates the file offset to the value specified by
+ * @offset and @origin under i_mutex.
+ */
+loff_t generic_file_llseek(struct file *file, loff_t offset, int origin)
 {
-       long long retval;
+       loff_t rval;
 
-       lock_kernel();
-       switch (origin) {
-               case 2:
-                       offset += i_size_read(file->f_path.dentry->d_inode);
-                       break;
-               case 1:
-                       offset += file->f_pos;
-       }
-       retval = -EINVAL;
-       if (offset>=0 && offset<=file->f_path.dentry->d_inode->i_sb->s_maxbytes) {
-               if (offset != file->f_pos) {
-                       file->f_pos = offset;
-                       file->f_version = 0;
-               }
-               retval = offset;
-       }
-       unlock_kernel();
-       return retval;
+       mutex_lock(&file->f_dentry->d_inode->i_mutex);
+       rval = generic_file_llseek_unlocked(file, offset, origin);
+       mutex_unlock(&file->f_dentry->d_inode->i_mutex);
+
+       return rval;
 }
-EXPORT_SYMBOL(remote_llseek);
+EXPORT_SYMBOL(generic_file_llseek);
 
 loff_t no_llseek(struct file *file, loff_t offset, int origin)
 {
@@ -90,14 +105,18 @@ EXPORT_SYMBOL(no_llseek);
 
 loff_t default_llseek(struct file *file, loff_t offset, int origin)
 {
-       long long retval;
+       loff_t retval;
 
        lock_kernel();
        switch (origin) {
-               case 2:
+               case SEEK_END:
                        offset += i_size_read(file->f_path.dentry->d_inode);
                        break;
-               case 1:
+               case SEEK_CUR:
+                       if (offset == 0) {
+                               retval = file->f_pos;
+                               goto out;
+                       }
                        offset += file->f_pos;
        }
        retval = -EINVAL;
@@ -108,6 +127,7 @@ loff_t default_llseek(struct file *file, loff_t offset, int origin)
                }
                retval = offset;
        }
+out:
        unlock_kernel();
        return retval;
 }
@@ -127,7 +147,7 @@ loff_t vfs_llseek(struct file *file, loff_t offset, int origin)
 }
 EXPORT_SYMBOL(vfs_llseek);
 
-asmlinkage off_t sys_lseek(unsigned int fd, off_t offset, unsigned int origin)
+SYSCALL_DEFINE3(lseek, unsigned int, fd, off_t, offset, unsigned int, origin)
 {
        off_t retval;
        struct file * file;
@@ -139,7 +159,7 @@ asmlinkage off_t sys_lseek(unsigned int fd, off_t offset, unsigned int origin)
                goto bad;
 
        retval = -EINVAL;
-       if (origin <= 2) {
+       if (origin <= SEEK_MAX) {
                loff_t res = vfs_llseek(file, offset, origin);
                retval = res;
                if (res != (loff_t)retval)
@@ -151,9 +171,9 @@ bad:
 }
 
 #ifdef __ARCH_WANT_SYS_LLSEEK
-asmlinkage long sys_llseek(unsigned int fd, unsigned long offset_high,
-                          unsigned long offset_low, loff_t __user * result,
-                          unsigned int origin)
+SYSCALL_DEFINE5(llseek, unsigned int, fd, unsigned long, offset_high,
+               unsigned long, offset_low, loff_t __user *, result,
+               unsigned int, origin)
 {
        int retval;
        struct file * file;
@@ -166,7 +186,7 @@ asmlinkage long sys_llseek(unsigned int fd, unsigned long offset_high,
                goto bad;
 
        retval = -EINVAL;
-       if (origin > 2)
+       if (origin > SEEK_MAX)
                goto out_putf;
 
        offset = vfs_llseek(file, ((loff_t) offset_high << 32) | offset_low,
@@ -196,25 +216,27 @@ int rw_verify_area(int read_write, struct file *file, loff_t *ppos, size_t count
 {
        struct inode *inode;
        loff_t pos;
+       int retval = -EINVAL;
 
+       inode = file->f_path.dentry->d_inode;
        if (unlikely((ssize_t) count < 0))
-               goto Einval;
+               return retval;
        pos = *ppos;
        if (unlikely((pos < 0) || (loff_t) (pos + count) < 0))
-               goto Einval;
+               return retval;
 
-       inode = file->f_path.dentry->d_inode;
-       if (unlikely(inode->i_flock && MANDATORY_LOCK(inode))) {
-               int retval = locks_mandatory_area(
+       if (unlikely(inode->i_flock && mandatory_lock(inode))) {
+               retval = locks_mandatory_area(
                        read_write == READ ? FLOCK_VERIFY_READ : FLOCK_VERIFY_WRITE,
                        inode, file, pos, count);
                if (retval < 0)
                        return retval;
        }
+       retval = security_file_permission(file,
+                               read_write == READ ? MAY_READ : MAY_WRITE);
+       if (retval)
+               return retval;
        return count > MAX_RW_COUNT ? MAX_RW_COUNT : count;
-
-Einval:
-       return -EINVAL;
 }
 
 static void wait_on_retry_sync_kiocb(struct kiocb *iocb)
@@ -266,18 +288,15 @@ ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos)
        ret = rw_verify_area(READ, file, pos, count);
        if (ret >= 0) {
                count = ret;
-               ret = security_file_permission (file, MAY_READ);
-               if (!ret) {
-                       if (file->f_op->read)
-                               ret = file->f_op->read(file, buf, count, pos);
-                       else
-                               ret = do_sync_read(file, buf, count, pos);
-                       if (ret > 0) {
-                               fsnotify_access(file->f_path.dentry);
-                               add_rchar(current, ret);
-                       }
-                       inc_syscr(current);
+               if (file->f_op->read)
+                       ret = file->f_op->read(file, buf, count, pos);
+               else
+                       ret = do_sync_read(file, buf, count, pos);
+               if (ret > 0) {
+                       fsnotify_access(file->f_path.dentry);
+                       add_rchar(current, ret);
                }
+               inc_syscr(current);
        }
 
        return ret;
@@ -324,18 +343,15 @@ ssize_t vfs_write(struct file *file, const char __user *buf, size_t count, loff_
        ret = rw_verify_area(WRITE, file, pos, count);
        if (ret >= 0) {
                count = ret;
-               ret = security_file_permission (file, MAY_WRITE);
-               if (!ret) {
-                       if (file->f_op->write)
-                               ret = file->f_op->write(file, buf, count, pos);
-                       else
-                               ret = do_sync_write(file, buf, count, pos);
-                       if (ret > 0) {
-                               fsnotify_modify(file->f_path.dentry);
-                               add_wchar(current, ret);
-                       }
-                       inc_syscw(current);
+               if (file->f_op->write)
+                       ret = file->f_op->write(file, buf, count, pos);
+               else
+                       ret = do_sync_write(file, buf, count, pos);
+               if (ret > 0) {
+                       fsnotify_modify(file->f_path.dentry);
+                       add_wchar(current, ret);
                }
+               inc_syscw(current);
        }
 
        return ret;
@@ -353,7 +369,7 @@ static inline void file_pos_write(struct file *file, loff_t pos)
        file->f_pos = pos;
 }
 
-asmlinkage ssize_t sys_read(unsigned int fd, char __user * buf, size_t count)
+SYSCALL_DEFINE3(read, unsigned int, fd, char __user *, buf, size_t, count)
 {
        struct file *file;
        ssize_t ret = -EBADF;
@@ -369,9 +385,9 @@ asmlinkage ssize_t sys_read(unsigned int fd, char __user * buf, size_t count)
 
        return ret;
 }
-EXPORT_SYMBOL_GPL(sys_read);
 
-asmlinkage ssize_t sys_write(unsigned int fd, const char __user * buf, size_t count)
+SYSCALL_DEFINE3(write, unsigned int, fd, const char __user *, buf,
+               size_t, count)
 {
        struct file *file;
        ssize_t ret = -EBADF;
@@ -388,8 +404,8 @@ asmlinkage ssize_t sys_write(unsigned int fd, const char __user * buf, size_t co
        return ret;
 }
 
-asmlinkage ssize_t sys_pread64(unsigned int fd, char __user *buf,
-                            size_t count, loff_t pos)
+SYSCALL_DEFINE(pread64)(unsigned int fd, char __user *buf,
+                       size_t count, loff_t pos)
 {
        struct file *file;
        ssize_t ret = -EBADF;
@@ -408,9 +424,17 @@ asmlinkage ssize_t sys_pread64(unsigned int fd, char __user *buf,
 
        return ret;
 }
+#ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
+asmlinkage long SyS_pread64(long fd, long buf, long count, loff_t pos)
+{
+       return SYSC_pread64((unsigned int) fd, (char __user *) buf,
+                           (size_t) count, pos);
+}
+SYSCALL_ALIAS(sys_pread64, SyS_pread64);
+#endif
 
-asmlinkage ssize_t sys_pwrite64(unsigned int fd, const char __user *buf,
-                             size_t count, loff_t pos)
+SYSCALL_DEFINE(pwrite64)(unsigned int fd, const char __user *buf,
+                        size_t count, loff_t pos)
 {
        struct file *file;
        ssize_t ret = -EBADF;
@@ -429,6 +453,14 @@ asmlinkage ssize_t sys_pwrite64(unsigned int fd, const char __user *buf,
 
        return ret;
 }
+#ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
+asmlinkage long SyS_pwrite64(long fd, long buf, long count, loff_t pos)
+{
+       return SYSC_pwrite64((unsigned int) fd, (const char __user *) buf,
+                            (size_t) count, pos);
+}
+SYSCALL_ALIAS(sys_pwrite64, SyS_pwrite64);
+#endif
 
 /*
  * Reduce an iovec's length in-place.  Return the resulting number of segments
@@ -449,6 +481,7 @@ unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to)
        }
        return seg;
 }
+EXPORT_SYMBOL(iov_shorten);
 
 ssize_t do_sync_readv_writev(struct file *filp, const struct iovec *iov,
                unsigned long nr_segs, size_t len, loff_t *ppos, iov_fn_t fn)
@@ -602,9 +635,6 @@ static ssize_t do_readv_writev(int type, struct file *file,
        ret = rw_verify_area(type, file, pos, tot_len);
        if (ret < 0)
                goto out;
-       ret = security_file_permission(file, type == READ ? MAY_READ : MAY_WRITE);
-       if (ret)
-               goto out;
 
        fnv = NULL;
        if (type == READ) {
@@ -659,8 +689,8 @@ ssize_t vfs_writev(struct file *file, const struct iovec __user *vec,
 
 EXPORT_SYMBOL(vfs_writev);
 
-asmlinkage ssize_t
-sys_readv(unsigned long fd, const struct iovec __user *vec, unsigned long vlen)
+SYSCALL_DEFINE3(readv, unsigned long, fd, const struct iovec __user *, vec,
+               unsigned long, vlen)
 {
        struct file *file;
        ssize_t ret = -EBADF;
@@ -680,8 +710,8 @@ sys_readv(unsigned long fd, const struct iovec __user *vec, unsigned long vlen)
        return ret;
 }
 
-asmlinkage ssize_t
-sys_writev(unsigned long fd, const struct iovec __user *vec, unsigned long vlen)
+SYSCALL_DEFINE3(writev, unsigned long, fd, const struct iovec __user *, vec,
+               unsigned long, vlen)
 {
        struct file *file;
        ssize_t ret = -EBADF;
@@ -701,6 +731,62 @@ sys_writev(unsigned long fd, const struct iovec __user *vec, unsigned long vlen)
        return ret;
 }
 
+static inline loff_t pos_from_hilo(unsigned long high, unsigned long low)
+{
+#define HALF_LONG_BITS (BITS_PER_LONG / 2)
+       return (((loff_t)high << HALF_LONG_BITS) << HALF_LONG_BITS) | low;
+}
+
+SYSCALL_DEFINE5(preadv, unsigned long, fd, const struct iovec __user *, vec,
+               unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h)
+{
+       loff_t pos = pos_from_hilo(pos_h, pos_l);
+       struct file *file;
+       ssize_t ret = -EBADF;
+       int fput_needed;
+
+       if (pos < 0)
+               return -EINVAL;
+
+       file = fget_light(fd, &fput_needed);
+       if (file) {
+               ret = -ESPIPE;
+               if (file->f_mode & FMODE_PREAD)
+                       ret = vfs_readv(file, vec, vlen, &pos);
+               fput_light(file, fput_needed);
+       }
+
+       if (ret > 0)
+               add_rchar(current, ret);
+       inc_syscr(current);
+       return ret;
+}
+
+SYSCALL_DEFINE5(pwritev, unsigned long, fd, const struct iovec __user *, vec,
+               unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h)
+{
+       loff_t pos = pos_from_hilo(pos_h, pos_l);
+       struct file *file;
+       ssize_t ret = -EBADF;
+       int fput_needed;
+
+       if (pos < 0)
+               return -EINVAL;
+
+       file = fget_light(fd, &fput_needed);
+       if (file) {
+               ret = -ESPIPE;
+               if (file->f_mode & FMODE_PWRITE)
+                       ret = vfs_writev(file, vec, vlen, &pos);
+               fput_light(file, fput_needed);
+       }
+
+       if (ret > 0)
+               add_wchar(current, ret);
+       inc_syscw(current);
+       return ret;
+}
+
 static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
                           size_t count, loff_t max)
 {
@@ -708,7 +794,7 @@ static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
        struct inode * in_inode, * out_inode;
        loff_t pos;
        ssize_t retval;
-       int fput_needed_in, fput_needed_out;
+       int fput_needed_in, fput_needed_out, fl;
 
        /*
         * Get input file, and verify that it is ok..
@@ -719,12 +805,6 @@ static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
                goto out;
        if (!(in_file->f_mode & FMODE_READ))
                goto fput_in;
-       retval = -EINVAL;
-       in_inode = in_file->f_path.dentry->d_inode;
-       if (!in_inode)
-               goto fput_in;
-       if (!in_file->f_op || !in_file->f_op->sendfile)
-               goto fput_in;
        retval = -ESPIPE;
        if (!ppos)
                ppos = &in_file->f_pos;
@@ -736,10 +816,6 @@ static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
                goto fput_in;
        count = retval;
 
-       retval = security_file_permission (in_file, MAY_READ);
-       if (retval)
-               goto fput_in;
-
        /*
         * Get output file, and verify that it is ok..
         */
@@ -750,25 +826,17 @@ static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
        if (!(out_file->f_mode & FMODE_WRITE))
                goto fput_out;
        retval = -EINVAL;
-       if (!out_file->f_op || !out_file->f_op->sendpage)
-               goto fput_out;
+       in_inode = in_file->f_path.dentry->d_inode;
        out_inode = out_file->f_path.dentry->d_inode;
        retval = rw_verify_area(WRITE, out_file, &out_file->f_pos, count);
        if (retval < 0)
                goto fput_out;
        count = retval;
 
-       retval = security_file_permission (out_file, MAY_WRITE);
-       if (retval)
-               goto fput_out;
-
        if (!max)
                max = min(in_inode->i_sb->s_maxbytes, out_inode->i_sb->s_maxbytes);
 
        pos = *ppos;
-       retval = -EINVAL;
-       if (unlikely(pos < 0))
-               goto fput_out;
        if (unlikely(pos + count > max)) {
                retval = -EOVERFLOW;
                if (pos >= max)
@@ -776,7 +844,18 @@ static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
                count = max - pos;
        }
 
-       retval = in_file->f_op->sendfile(in_file, ppos, count, file_send_actor, out_file);
+       fl = 0;
+#if 0
+       /*
+        * We need to debate whether we can enable this or not. The
+        * man page documents EAGAIN return for the output at least,
+        * and the application is arguably buggy if it doesn't expect
+        * EAGAIN on a non-blocking file descriptor.
+        */
+       if (in_file->f_flags & O_NONBLOCK)
+               fl = SPLICE_F_NONBLOCK;
+#endif
+       retval = do_splice_direct(in_file, ppos, out_file, count, fl);
 
        if (retval > 0) {
                add_rchar(current, retval);
@@ -796,7 +875,7 @@ out:
        return retval;
 }
 
-asmlinkage ssize_t sys_sendfile(int out_fd, int in_fd, off_t __user *offset, size_t count)
+SYSCALL_DEFINE4(sendfile, int, out_fd, int, in_fd, off_t __user *, offset, size_t, count)
 {
        loff_t pos;
        off_t off;
@@ -815,7 +894,7 @@ asmlinkage ssize_t sys_sendfile(int out_fd, int in_fd, off_t __user *offset, siz
        return do_sendfile(out_fd, in_fd, NULL, count, 0);
 }
 
-asmlinkage ssize_t sys_sendfile64(int out_fd, int in_fd, loff_t __user *offset, size_t count)
+SYSCALL_DEFINE4(sendfile64, int, out_fd, int, in_fd, loff_t __user *, offset, size_t, count)
 {
        loff_t pos;
        ssize_t ret;