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author | Ravishankar N <ravishankar@redhat.com> | 2015-06-30 21:10:22 +0300 |
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committer | Miklos Szeredi <miklos@szeredi.hu> | 2015-11-10 12:32:37 +0300 |
commit | 0b5da8db145bfd44266ac964a2636a0cf8d7c286 (patch) | |
tree | 23e46abfcb58f4b744aeab42a8c3a62e141b399b /fs | |
parent | 3ca8138f014a913f98e6ef40e939868e1e9ea876 (diff) | |
download | linux-0b5da8db145bfd44266ac964a2636a0cf8d7c286.tar.xz |
fuse: add support for SEEK_HOLE and SEEK_DATA in lseek
A useful performance improvement for accessing virtual machine images
via FUSE mount.
See https://bugzilla.redhat.com/show_bug.cgi?id=1220173 for a use-case
for glusterFS.
Signed-off-by: Ravishankar N <ravishankar@redhat.com>
Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Diffstat (limited to 'fs')
-rw-r--r-- | fs/fuse/file.c | 73 | ||||
-rw-r--r-- | fs/fuse/fuse_i.h | 3 |
2 files changed, 68 insertions, 8 deletions
diff --git a/fs/fuse/file.c b/fs/fuse/file.c index 195476a24148..47f181191060 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -2231,20 +2231,77 @@ static sector_t fuse_bmap(struct address_space *mapping, sector_t block) return err ? 0 : outarg.block; } +static loff_t fuse_lseek(struct file *file, loff_t offset, int whence) +{ + struct inode *inode = file->f_mapping->host; + struct fuse_conn *fc = get_fuse_conn(inode); + struct fuse_file *ff = file->private_data; + FUSE_ARGS(args); + struct fuse_lseek_in inarg = { + .fh = ff->fh, + .offset = offset, + .whence = whence + }; + struct fuse_lseek_out outarg; + int err; + + if (fc->no_lseek) + goto fallback; + + args.in.h.opcode = FUSE_LSEEK; + args.in.h.nodeid = ff->nodeid; + args.in.numargs = 1; + args.in.args[0].size = sizeof(inarg); + args.in.args[0].value = &inarg; + args.out.numargs = 1; + args.out.args[0].size = sizeof(outarg); + args.out.args[0].value = &outarg; + err = fuse_simple_request(fc, &args); + if (err) { + if (err == -ENOSYS) { + fc->no_lseek = 1; + goto fallback; + } + return err; + } + + return vfs_setpos(file, outarg.offset, inode->i_sb->s_maxbytes); + +fallback: + err = fuse_update_attributes(inode, NULL, file, NULL); + if (!err) + return generic_file_llseek(file, offset, whence); + else + return err; +} + static loff_t fuse_file_llseek(struct file *file, loff_t offset, int whence) { loff_t retval; struct inode *inode = file_inode(file); - /* No i_mutex protection necessary for SEEK_CUR and SEEK_SET */ - if (whence == SEEK_CUR || whence == SEEK_SET) - return generic_file_llseek(file, offset, whence); - - mutex_lock(&inode->i_mutex); - retval = fuse_update_attributes(inode, NULL, file, NULL); - if (!retval) + switch (whence) { + case SEEK_SET: + case SEEK_CUR: + /* No i_mutex protection necessary for SEEK_CUR and SEEK_SET */ retval = generic_file_llseek(file, offset, whence); - mutex_unlock(&inode->i_mutex); + break; + case SEEK_END: + mutex_lock(&inode->i_mutex); + retval = fuse_update_attributes(inode, NULL, file, NULL); + if (!retval) + retval = generic_file_llseek(file, offset, whence); + mutex_unlock(&inode->i_mutex); + break; + case SEEK_HOLE: + case SEEK_DATA: + mutex_lock(&inode->i_mutex); + retval = fuse_lseek(file, offset, whence); + mutex_unlock(&inode->i_mutex); + break; + default: + retval = -EINVAL; + } return retval; } diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h index 405113101db8..ce394b5fe6b4 100644 --- a/fs/fuse/fuse_i.h +++ b/fs/fuse/fuse_i.h @@ -605,6 +605,9 @@ struct fuse_conn { /** Does the filesystem support asynchronous direct-IO submission? */ unsigned async_dio:1; + /** Is lseek not implemented by fs? */ + unsigned no_lseek:1; + /** The number of requests waiting for completion */ atomic_t num_waiting; |