It seems that systemd needs tmpfs to support fallocate, see http://lkml.org/lkml/2011/10/20/275. This patch adds fallocate support to tmpfs. As we already have shmem_truncate_range(), it is also easy to add FALLOC_FL_PUNCH_HOLE support too. Cc: Pekka Enberg <penberg@xxxxxxxxxx> Cc: Hugh Dickins <hughd@xxxxxxxxxx> Cc: Dave Hansen <dave@xxxxxxxxxxxxxxxxxx> Cc: Lennart Poettering <lennart@xxxxxxxxxxxxxx> Cc: Kay Sievers <kay.sievers@xxxxxxxx> Cc: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx> Signed-off-by: WANG Cong <amwang@xxxxxxxxxx> --- mm/shmem.c | 43 +++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 43 insertions(+), 0 deletions(-) diff --git a/mm/shmem.c b/mm/shmem.c index d672250..96bf619 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -30,6 +30,7 @@ #include <linux/mm.h> #include <linux/export.h> #include <linux/swap.h> +#include <linux/falloc.h> static struct vfsmount *shm_mnt; @@ -1431,6 +1432,47 @@ static ssize_t shmem_file_splice_read(struct file *in, loff_t *ppos, return error; } +static long shmem_fallocate(struct file *file, int mode, + loff_t offset, loff_t len) +{ + struct inode *inode = file->f_path.dentry->d_inode; + pgoff_t start = offset >> PAGE_CACHE_SHIFT; + pgoff_t end = DIV_ROUND_UP((offset + len), PAGE_CACHE_SIZE); + pgoff_t index = start; + loff_t i_size = i_size_read(inode); + struct page *page = NULL; + int ret = 0; + + mutex_lock(&inode->i_mutex); + if (mode & FALLOC_FL_PUNCH_HOLE) { + if (!(offset > i_size || (end << PAGE_CACHE_SHIFT) > i_size)) + shmem_truncate_range(inode, offset, + (end << PAGE_CACHE_SHIFT) - 1); + goto unlock; + } + + if (!(mode & FALLOC_FL_KEEP_SIZE)) { + ret = inode_newsize_ok(inode, (offset + len)); + if (ret) + goto unlock; + } + + while (index < end) { + ret = shmem_getpage(inode, index, &page, SGP_WRITE, NULL); + if (ret) + goto unlock; + if (page) + unlock_page(page); + index++; + } + if (!(mode & FALLOC_FL_KEEP_SIZE) && (index << PAGE_CACHE_SHIFT) > i_size) + i_size_write(inode, index << PAGE_CACHE_SHIFT); + +unlock: + mutex_unlock(&inode->i_mutex); + return ret; +} + static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf) { struct shmem_sb_info *sbinfo = SHMEM_SB(dentry->d_sb); @@ -2286,6 +2328,7 @@ static const struct file_operations shmem_file_operations = { .fsync = noop_fsync, .splice_read = shmem_file_splice_read, .splice_write = generic_file_splice_write, + .fallocate = shmem_fallocate, #endif }; -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>