diff options
Diffstat (limited to 'fs/fat/file.c')
| -rw-r--r-- | fs/fat/file.c | 108 |
1 files changed, 107 insertions, 1 deletions
diff --git a/fs/fat/file.c b/fs/fat/file.c index b0b632e50ddb..73264395f705 100644 --- a/fs/fat/file.c +++ b/fs/fat/file.c @@ -17,8 +17,11 @@ #include <linux/blkdev.h> #include <linux/fsnotify.h> #include <linux/security.h> +#include <linux/falloc.h> #include "fat.h" +static long fat_fallocate(struct file *file, int mode, + loff_t offset, loff_t len); static int fat_ioctl_get_attributes(struct inode *inode, u32 __user *user_attr) { u32 attr; @@ -140,6 +143,22 @@ static long fat_generic_compat_ioctl(struct file *filp, unsigned int cmd, static int fat_file_release(struct inode *inode, struct file *filp) { + + struct super_block *sb = inode->i_sb; + loff_t mmu_private_ideal; + + /* + * Release unwritten fallocated blocks on file release. + * Do this only when the last open file descriptor is closed. + */ + mutex_lock(&inode->i_mutex); + mmu_private_ideal = round_up(inode->i_size, sb->s_blocksize); + + if (mmu_private_ideal < MSDOS_I(inode)->mmu_private && + filp->f_dentry->d_count == 1) + fat_truncate_blocks(inode, inode->i_size); + mutex_unlock(&inode->i_mutex); + if ((filp->f_mode & FMODE_WRITE) && MSDOS_SB(inode->i_sb)->options.flush) { fat_flush_inodes(inode->i_sb, inode, NULL); @@ -174,6 +193,7 @@ const struct file_operations fat_file_operations = { #endif .fsync = fat_file_fsync, .splice_read = generic_file_splice_read, + .fallocate = fat_fallocate, }; static int fat_cont_expand(struct inode *inode, loff_t size) @@ -212,6 +232,88 @@ out: return err; } +/* + * Preallocate space for a file. This implements fat's fallocate file + * operation, which gets called from sys_fallocate system call. User + * space requests len bytes at offset. If FALLOC_FL_KEEP_SIZE is set + * we just allocate clusters without zeroing them out. Otherwise we + * allocate and zero out clusters via an expanding truncate. The + * allocated clusters are freed in fat_file_release(). + */ +static long fat_fallocate(struct file *file, int mode, + loff_t offset, loff_t len) +{ + int cluster, fclus, dclus; + int nr_cluster; /* Number of clusters to be allocated */ + loff_t nr_bytes; /* Number of bytes to be allocated*/ + loff_t free_bytes; /* Unused bytes in the last cluster of file*/ + struct inode *inode = file->f_mapping->host; + struct super_block *sb = inode->i_sb; + struct msdos_sb_info *sbi = MSDOS_SB(sb); + int err = 0; + + /* No support for hole punch or other fallocate flags. */ + if (mode & ~FALLOC_FL_KEEP_SIZE) + return -EOPNOTSUPP; + + mutex_lock(&inode->i_mutex); + if ((offset + len) <= MSDOS_I(inode)->mmu_private) { + fat_msg(sb, KERN_ERR, + "fat_fallocate(): Blocks already allocated"); + err = -EINVAL; + goto error; + } + + if (mode & FALLOC_FL_KEEP_SIZE) { + /* First compute the number of clusters to be allocated */ + if (inode->i_size > 0) { + err = fat_get_cluster(inode, FAT_ENT_EOF, + &fclus, &dclus); + if (err < 0) { + fat_msg(sb, KERN_ERR, + "fat_fallocate(): fat_get_cluster() error"); + goto error; + } + free_bytes = ((fclus + 1) << sbi->cluster_bits) - + inode->i_size; + nr_bytes = offset + len - inode->i_size - free_bytes; + MSDOS_I(inode)->mmu_private = (fclus + 1) << + sbi->cluster_bits; + } else + nr_bytes = offset + len - inode->i_size; + + nr_cluster = (nr_bytes + (sbi->cluster_size - 1)) >> + sbi->cluster_bits; + + /* Start the allocation.We are not zeroing out the clusters */ + while (nr_cluster-- > 0) { + err = fat_alloc_clusters(inode, &cluster, 1); + if (err) { + fat_msg(sb, KERN_ERR, + "fat_fallocate(): fat_alloc_clusters() error"); + goto error; + } + err = fat_chain_add(inode, cluster, 1); + if (err) { + fat_free_clusters(inode, cluster); + goto error; + } + MSDOS_I(inode)->mmu_private += sbi->cluster_size; + } + } else { + /* This is just an expanding truncate */ + err = fat_cont_expand(inode, (offset + len)); + if (err) { + fat_msg(sb, KERN_ERR, + "fat_fallocate(): fat_cont_expand() error"); + } + } + +error: + mutex_unlock(&inode->i_mutex); + return err; +} + /* Free all clusters after the skip'th cluster. */ static int fat_free(struct inode *inode, int skip) { @@ -378,6 +480,9 @@ int fat_setattr(struct dentry *dentry, struct iattr *attr) struct inode *inode = dentry->d_inode; unsigned int ia_valid; int error; + loff_t mmu_private_ideal; + + mmu_private_ideal = round_up(inode->i_size, dentry->d_sb->s_blocksize); /* Check for setting the inode time. */ ia_valid = attr->ia_valid; @@ -403,7 +508,8 @@ int fat_setattr(struct dentry *dentry, struct iattr *attr) if (attr->ia_valid & ATTR_SIZE) { inode_dio_wait(inode); - if (attr->ia_size > inode->i_size) { + if (attr->ia_size > inode->i_size && + MSDOS_I(inode)->mmu_private <= mmu_private_ideal) { error = fat_cont_expand(inode, attr->ia_size); if (error || attr->ia_valid == ATTR_SIZE) goto out; |