X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=fs%2Fsync.c;h=dd200025af8521d65e7bf28efceaece55994c59d;hb=64424289dd2e37b4800df1f7f2ef4fe550f58729;hp=aab5ffe77e9fd67e3ac9173a4cb9488fd393f074;hpb=5246d0503130fa58904c8beb987fcf93b96d8ab6;p=safe%2Fjmp%2Flinux-2.6 diff --git a/fs/sync.c b/fs/sync.c index aab5ffe..dd20002 100644 --- a/fs/sync.c +++ b/fs/sync.c @@ -6,15 +6,250 @@ #include #include #include +#include #include #include #include #include +#include +#include +#include "internal.h" #define VALID_FLAGS (SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE| \ SYNC_FILE_RANGE_WAIT_AFTER) /* + * Do the filesystem syncing work. For simple filesystems sync_inodes_sb(sb, 0) + * just dirties buffers with inodes so we have to submit IO for these buffers + * via __sync_blockdev(). This also speeds up the wait == 1 case since in that + * case write_inode() functions do sync_dirty_buffer() and thus effectively + * write one block at a time. + */ +static int __sync_filesystem(struct super_block *sb, int wait) +{ + /* Avoid doing twice syncing and cache pruning for quota sync */ + if (!wait) + writeout_quota_sb(sb, -1); + else + sync_quota_sb(sb, -1); + sync_inodes_sb(sb, wait); + if (sb->s_op->sync_fs) + sb->s_op->sync_fs(sb, wait); + return __sync_blockdev(sb->s_bdev, wait); +} + +/* + * Write out and wait upon all dirty data associated with this + * superblock. Filesystem data as well as the underlying block + * device. Takes the superblock lock. + */ +int sync_filesystem(struct super_block *sb) +{ + int ret; + + /* + * We need to be protected against the filesystem going from + * r/o to r/w or vice versa. + */ + WARN_ON(!rwsem_is_locked(&sb->s_umount)); + + /* + * No point in syncing out anything if the filesystem is read-only. + */ + if (sb->s_flags & MS_RDONLY) + return 0; + + ret = __sync_filesystem(sb, 0); + if (ret < 0) + return ret; + return __sync_filesystem(sb, 1); +} +EXPORT_SYMBOL_GPL(sync_filesystem); + +/* + * Sync all the data for all the filesystems (called by sys_sync() and + * emergency sync) + * + * This operation is careful to avoid the livelock which could easily happen + * if two or more filesystems are being continuously dirtied. s_need_sync + * is used only here. We set it against all filesystems and then clear it as + * we sync them. So redirtied filesystems are skipped. + * + * But if process A is currently running sync_filesystems and then process B + * calls sync_filesystems as well, process B will set all the s_need_sync + * flags again, which will cause process A to resync everything. Fix that with + * a local mutex. + */ +static void sync_filesystems(int wait) +{ + struct super_block *sb; + static DEFINE_MUTEX(mutex); + + mutex_lock(&mutex); /* Could be down_interruptible */ + spin_lock(&sb_lock); + list_for_each_entry(sb, &super_blocks, s_list) + sb->s_need_sync = 1; + +restart: + list_for_each_entry(sb, &super_blocks, s_list) { + if (!sb->s_need_sync) + continue; + sb->s_need_sync = 0; + sb->s_count++; + spin_unlock(&sb_lock); + + down_read(&sb->s_umount); + if (!(sb->s_flags & MS_RDONLY) && sb->s_root) + __sync_filesystem(sb, wait); + up_read(&sb->s_umount); + + /* restart only when sb is no longer on the list */ + spin_lock(&sb_lock); + if (__put_super_and_need_restart(sb)) + goto restart; + } + spin_unlock(&sb_lock); + mutex_unlock(&mutex); +} + +SYSCALL_DEFINE0(sync) +{ + sync_filesystems(0); + sync_filesystems(1); + if (unlikely(laptop_mode)) + laptop_sync_completion(); + return 0; +} + +static void do_sync_work(struct work_struct *work) +{ + /* + * Sync twice to reduce the possibility we skipped some inodes / pages + * because they were temporarily locked + */ + sync_filesystems(0); + sync_filesystems(0); + printk("Emergency Sync complete\n"); + kfree(work); +} + +void emergency_sync(void) +{ + struct work_struct *work; + + work = kmalloc(sizeof(*work), GFP_ATOMIC); + if (work) { + INIT_WORK(work, do_sync_work); + schedule_work(work); + } +} + +/* + * Generic function to fsync a file. + * + * filp may be NULL if called via the msync of a vma. + */ +int file_fsync(struct file *filp, struct dentry *dentry, int datasync) +{ + struct inode * inode = dentry->d_inode; + struct super_block * sb; + int ret, err; + + /* sync the inode to buffers */ + ret = write_inode_now(inode, 0); + + /* sync the superblock to buffers */ + sb = inode->i_sb; + if (sb->s_dirt && sb->s_op->write_super) + sb->s_op->write_super(sb); + + /* .. finally sync the buffers to disk */ + err = sync_blockdev(sb->s_bdev); + if (!ret) + ret = err; + return ret; +} + +/** + * vfs_fsync - perform a fsync or fdatasync on a file + * @file: file to sync + * @dentry: dentry of @file + * @data: only perform a fdatasync operation + * + * Write back data and metadata for @file to disk. If @datasync is + * set only metadata needed to access modified file data is written. + * + * In case this function is called from nfsd @file may be %NULL and + * only @dentry is set. This can only happen when the filesystem + * implements the export_operations API. + */ +int vfs_fsync(struct file *file, struct dentry *dentry, int datasync) +{ + const struct file_operations *fop; + struct address_space *mapping; + int err, ret; + + /* + * Get mapping and operations from the file in case we have + * as file, or get the default values for them in case we + * don't have a struct file available. Damn nfsd.. + */ + if (file) { + mapping = file->f_mapping; + fop = file->f_op; + } else { + mapping = dentry->d_inode->i_mapping; + fop = dentry->d_inode->i_fop; + } + + if (!fop || !fop->fsync) { + ret = -EINVAL; + goto out; + } + + ret = filemap_fdatawrite(mapping); + + /* + * We need to protect against concurrent writers, which could cause + * livelocks in fsync_buffers_list(). + */ + mutex_lock(&mapping->host->i_mutex); + err = fop->fsync(file, dentry, datasync); + if (!ret) + ret = err; + mutex_unlock(&mapping->host->i_mutex); + err = filemap_fdatawait(mapping); + if (!ret) + ret = err; +out: + return ret; +} +EXPORT_SYMBOL(vfs_fsync); + +static int do_fsync(unsigned int fd, int datasync) +{ + struct file *file; + int ret = -EBADF; + + file = fget(fd); + if (file) { + ret = vfs_fsync(file, file->f_path.dentry, datasync); + fput(file); + } + return ret; +} + +SYSCALL_DEFINE1(fsync, unsigned int, fd) +{ + return do_fsync(fd, 0); +} + +SYSCALL_DEFINE1(fdatasync, unsigned int, fd) +{ + return do_fsync(fd, 1); +} + +/* * sys_sync_file_range() permits finely controlled syncing over a segment of * a file in the range offset .. (offset+nbytes-1) inclusive. If nbytes is * zero then sys_sync_file_range() will operate from offset out to EOF. @@ -25,7 +260,8 @@ * before performing the write. * * SYNC_FILE_RANGE_WRITE: initiate writeout of all those dirty pages in the - * range which are not presently under writeback. + * range which are not presently under writeback. Note that this may block for + * significant periods due to exhaustion of disk request structures. * * SYNC_FILE_RANGE_WAIT_AFTER: wait upon writeout of all pages in the range * after performing the write. @@ -60,8 +296,8 @@ * already-instantiated disk blocks, there are no guarantees here that the data * will be available after a crash. */ -asmlinkage long sys_sync_file_range(int fd, loff_t offset, loff_t nbytes, - unsigned int flags) +SYSCALL_DEFINE(sync_file_range)(int fd, loff_t offset, loff_t nbytes, + unsigned int flags) { int ret; struct file *file; @@ -100,7 +336,7 @@ asmlinkage long sys_sync_file_range(int fd, loff_t offset, loff_t nbytes, } if (nbytes == 0) - endbyte = -1; + endbyte = LLONG_MAX; else endbyte--; /* inclusive */ @@ -109,29 +345,53 @@ asmlinkage long sys_sync_file_range(int fd, loff_t offset, loff_t nbytes, if (!file) goto out; - i_mode = file->f_dentry->d_inode->i_mode; + i_mode = file->f_path.dentry->d_inode->i_mode; ret = -ESPIPE; if (!S_ISREG(i_mode) && !S_ISBLK(i_mode) && !S_ISDIR(i_mode) && !S_ISLNK(i_mode)) goto out_put; - ret = do_sync_file_range(file, offset, endbyte, flags); + ret = do_sync_mapping_range(file->f_mapping, offset, endbyte, flags); out_put: fput_light(file, fput_needed); out: return ret; } +#ifdef CONFIG_HAVE_SYSCALL_WRAPPERS +asmlinkage long SyS_sync_file_range(long fd, loff_t offset, loff_t nbytes, + long flags) +{ + return SYSC_sync_file_range((int) fd, offset, nbytes, + (unsigned int) flags); +} +SYSCALL_ALIAS(sys_sync_file_range, SyS_sync_file_range); +#endif + +/* It would be nice if people remember that not all the world's an i386 + when they introduce new system calls */ +SYSCALL_DEFINE(sync_file_range2)(int fd, unsigned int flags, + loff_t offset, loff_t nbytes) +{ + return sys_sync_file_range(fd, offset, nbytes, flags); +} +#ifdef CONFIG_HAVE_SYSCALL_WRAPPERS +asmlinkage long SyS_sync_file_range2(long fd, long flags, + loff_t offset, loff_t nbytes) +{ + return SYSC_sync_file_range2((int) fd, (unsigned int) flags, + offset, nbytes); +} +SYSCALL_ALIAS(sys_sync_file_range2, SyS_sync_file_range2); +#endif /* * `endbyte' is inclusive */ -int do_sync_file_range(struct file *file, loff_t offset, loff_t endbyte, - unsigned int flags) +int do_sync_mapping_range(struct address_space *mapping, loff_t offset, + loff_t endbyte, unsigned int flags) { int ret; - struct address_space *mapping; - mapping = file->f_mapping; if (!mapping) { ret = -EINVAL; goto out; @@ -148,7 +408,7 @@ int do_sync_file_range(struct file *file, loff_t offset, loff_t endbyte, if (flags & SYNC_FILE_RANGE_WRITE) { ret = __filemap_fdatawrite_range(mapping, offset, endbyte, - WB_SYNC_NONE); + WB_SYNC_ALL); if (ret < 0) goto out; } @@ -161,4 +421,4 @@ int do_sync_file_range(struct file *file, loff_t offset, loff_t endbyte, out: return ret; } -EXPORT_SYMBOL_GPL(do_sync_file_range); +EXPORT_SYMBOL_GPL(do_sync_mapping_range);