Message ID | 4B77E0E6.1090701@redhat.com |
---|---|
State | New |
Headers | show |
On 02/14/2010 05:39 AM, Naphtali Sprei wrote: > Open backing file read-only where possible > Upgrade backing file to read-write during commit, back to read-only after commit > If upgrade fail, back to read-only. If also fail, "disconnect" the drive. > > Signed-off-by: Naphtali Sprei<nsprei@redhat.com> > Applied. Thanks. Regards, Anthony Liguori > --- > block.c | 83 ++++++++++++++++++++++++++++++++++++++++++++++++++-------- > block_int.h | 2 + > 2 files changed, 73 insertions(+), 12 deletions(-) > > diff --git a/block.c b/block.c > index af56ea7..31d1ba4 100644 > --- a/block.c > +++ b/block.c > @@ -363,6 +363,7 @@ int bdrv_open2(BlockDriverState *bs, const char *filename, int flags, > bs->is_temporary = 0; > bs->encrypted = 0; > bs->valid_key = 0; > + bs->open_flags = flags; > /* buffer_alignment defaulted to 512, drivers can change this value */ > bs->buffer_alignment = 512; > > @@ -450,8 +451,6 @@ int bdrv_open2(BlockDriverState *bs, const char *filename, int flags, > if (flags& (BDRV_O_CACHE_WB|BDRV_O_NOCACHE)) > bs->enable_write_cache = 1; > > - bs->read_only = (flags& BDRV_O_RDWR) == 0; > - > /* > * Clear flags that are internal to the block layer before opening the > * image. > @@ -472,6 +471,7 @@ int bdrv_open2(BlockDriverState *bs, const char *filename, int flags, > goto free_and_fail; > } > > + bs->keep_read_only = bs->read_only = !(open_flags& BDRV_O_RDWR); > if (drv->bdrv_getlength) { > bs->total_sectors = bdrv_getlength(bs)>> BDRV_SECTOR_BITS; > } > @@ -488,13 +488,22 @@ int bdrv_open2(BlockDriverState *bs, const char *filename, int flags, > filename, bs->backing_file); > if (bs->backing_format[0] != '\0') > back_drv = bdrv_find_format(bs->backing_format); > + > + /* backing files always opened read-only */ > + open_flags&= ~BDRV_O_RDWR; > + > ret = bdrv_open2(bs->backing_hd, backing_filename, open_flags, > back_drv); > - bs->backing_hd->read_only = (open_flags& BDRV_O_RDWR) == 0; > if (ret< 0) { > bdrv_close(bs); > return ret; > } > + if (bs->is_temporary) { > + bs->backing_hd->keep_read_only = !(flags& BDRV_O_RDWR); > + } else { > + /* base image inherits from "parent" */ > + bs->backing_hd->keep_read_only = bs->keep_read_only; > + } > } > > if (!bdrv_key_required(bs)) { > @@ -570,19 +579,48 @@ int bdrv_commit(BlockDriverState *bs) > { > BlockDriver *drv = bs->drv; > int64_t i, total_sectors; > - int n, j; > - int ret = 0; > + int n, j, ro, open_flags; > + int ret = 0, rw_ret = 0; > unsigned char sector[512]; > + char filename[1024]; > + BlockDriverState *bs_rw, *bs_ro; > > if (!drv) > return -ENOMEDIUM; > - > - if (bs->read_only) { > - return -EACCES; > + > + if (!bs->backing_hd) { > + return -ENOTSUP; > } > > - if (!bs->backing_hd) { > - return -ENOTSUP; > + if (bs->backing_hd->keep_read_only) { > + return -EACCES; > + } > + > + ro = bs->backing_hd->read_only; > + strncpy(filename, bs->backing_hd->filename, sizeof(filename)); > + open_flags = bs->backing_hd->open_flags; > + > + if (ro) { > + /* re-open as RW */ > + bdrv_delete(bs->backing_hd); > + bs->backing_hd = NULL; > + bs_rw = bdrv_new(""); > + rw_ret = bdrv_open2(bs_rw, filename, open_flags | BDRV_O_RDWR, NULL); > + if (rw_ret< 0) { > + bdrv_delete(bs_rw); > + /* try to re-open read-only */ > + bs_ro = bdrv_new(""); > + ret = bdrv_open2(bs_ro, filename, open_flags& ~BDRV_O_RDWR, NULL); > + if (ret< 0) { > + bdrv_delete(bs_ro); > + /* drive not functional anymore */ > + bs->drv = NULL; > + return ret; > + } > + bs->backing_hd = bs_ro; > + return rw_ret; > + } > + bs->backing_hd = bs_rw; > } > > total_sectors = bdrv_getlength(bs)>> BDRV_SECTOR_BITS; > @@ -590,11 +628,13 @@ int bdrv_commit(BlockDriverState *bs) > if (drv->bdrv_is_allocated(bs, i, 65536,&n)) { > for(j = 0; j< n; j++) { > if (bdrv_read(bs, i, sector, 1) != 0) { > - return -EIO; > + ret = -EIO; > + goto ro_cleanup; > } > > if (bdrv_write(bs->backing_hd, i, sector, 1) != 0) { > - return -EIO; > + ret = -EIO; > + goto ro_cleanup; > } > i++; > } > @@ -614,6 +654,25 @@ int bdrv_commit(BlockDriverState *bs) > */ > if (bs->backing_hd) > bdrv_flush(bs->backing_hd); > + > +ro_cleanup: > + > + if (ro) { > + /* re-open as RO */ > + bdrv_delete(bs->backing_hd); > + bs->backing_hd = NULL; > + bs_ro = bdrv_new(""); > + ret = bdrv_open2(bs_ro, filename, open_flags& ~BDRV_O_RDWR, NULL); > + if (ret< 0) { > + bdrv_delete(bs_ro); > + /* drive not functional anymore */ > + bs->drv = NULL; > + return ret; > + } > + bs->backing_hd = bs_ro; > + bs->backing_hd->keep_read_only = 0; > + } > + > return ret; > } > > diff --git a/block_int.h b/block_int.h > index 930a5a4..50e1a0b 100644 > --- a/block_int.h > +++ b/block_int.h > @@ -130,6 +130,8 @@ struct BlockDriverState { > int64_t total_sectors; /* if we are reading a disk image, give its > size in sectors */ > int read_only; /* if true, the media is read only */ > + int keep_read_only; /* if true, the media was requested to stay read only */ > + int open_flags; /* flags used to open the file, re-used for re-open */ > int removable; /* if true, the media can be removed */ > int locked; /* if true, the media cannot temporarily be ejected */ > int encrypted; /* if true, the media is encrypted */ >
diff --git a/block.c b/block.c index af56ea7..31d1ba4 100644 --- a/block.c +++ b/block.c @@ -363,6 +363,7 @@ int bdrv_open2(BlockDriverState *bs, const char *filename, int flags, bs->is_temporary = 0; bs->encrypted = 0; bs->valid_key = 0; + bs->open_flags = flags; /* buffer_alignment defaulted to 512, drivers can change this value */ bs->buffer_alignment = 512; @@ -450,8 +451,6 @@ int bdrv_open2(BlockDriverState *bs, const char *filename, int flags, if (flags & (BDRV_O_CACHE_WB|BDRV_O_NOCACHE)) bs->enable_write_cache = 1; - bs->read_only = (flags & BDRV_O_RDWR) == 0; - /* * Clear flags that are internal to the block layer before opening the * image. @@ -472,6 +471,7 @@ int bdrv_open2(BlockDriverState *bs, const char *filename, int flags, goto free_and_fail; } + bs->keep_read_only = bs->read_only = !(open_flags & BDRV_O_RDWR); if (drv->bdrv_getlength) { bs->total_sectors = bdrv_getlength(bs) >> BDRV_SECTOR_BITS; } @@ -488,13 +488,22 @@ int bdrv_open2(BlockDriverState *bs, const char *filename, int flags, filename, bs->backing_file); if (bs->backing_format[0] != '\0') back_drv = bdrv_find_format(bs->backing_format); + + /* backing files always opened read-only */ + open_flags &= ~BDRV_O_RDWR; + ret = bdrv_open2(bs->backing_hd, backing_filename, open_flags, back_drv); - bs->backing_hd->read_only = (open_flags & BDRV_O_RDWR) == 0; if (ret < 0) { bdrv_close(bs); return ret; } + if (bs->is_temporary) { + bs->backing_hd->keep_read_only = !(flags & BDRV_O_RDWR); + } else { + /* base image inherits from "parent" */ + bs->backing_hd->keep_read_only = bs->keep_read_only; + } } if (!bdrv_key_required(bs)) { @@ -570,19 +579,48 @@ int bdrv_commit(BlockDriverState *bs) { BlockDriver *drv = bs->drv; int64_t i, total_sectors; - int n, j; - int ret = 0; + int n, j, ro, open_flags; + int ret = 0, rw_ret = 0; unsigned char sector[512]; + char filename[1024]; + BlockDriverState *bs_rw, *bs_ro; if (!drv) return -ENOMEDIUM; - - if (bs->read_only) { - return -EACCES; + + if (!bs->backing_hd) { + return -ENOTSUP; } - if (!bs->backing_hd) { - return -ENOTSUP; + if (bs->backing_hd->keep_read_only) { + return -EACCES; + } + + ro = bs->backing_hd->read_only; + strncpy(filename, bs->backing_hd->filename, sizeof(filename)); + open_flags = bs->backing_hd->open_flags; + + if (ro) { + /* re-open as RW */ + bdrv_delete(bs->backing_hd); + bs->backing_hd = NULL; + bs_rw = bdrv_new(""); + rw_ret = bdrv_open2(bs_rw, filename, open_flags | BDRV_O_RDWR, NULL); + if (rw_ret < 0) { + bdrv_delete(bs_rw); + /* try to re-open read-only */ + bs_ro = bdrv_new(""); + ret = bdrv_open2(bs_ro, filename, open_flags & ~BDRV_O_RDWR, NULL); + if (ret < 0) { + bdrv_delete(bs_ro); + /* drive not functional anymore */ + bs->drv = NULL; + return ret; + } + bs->backing_hd = bs_ro; + return rw_ret; + } + bs->backing_hd = bs_rw; } total_sectors = bdrv_getlength(bs) >> BDRV_SECTOR_BITS; @@ -590,11 +628,13 @@ int bdrv_commit(BlockDriverState *bs) if (drv->bdrv_is_allocated(bs, i, 65536, &n)) { for(j = 0; j < n; j++) { if (bdrv_read(bs, i, sector, 1) != 0) { - return -EIO; + ret = -EIO; + goto ro_cleanup; } if (bdrv_write(bs->backing_hd, i, sector, 1) != 0) { - return -EIO; + ret = -EIO; + goto ro_cleanup; } i++; } @@ -614,6 +654,25 @@ int bdrv_commit(BlockDriverState *bs) */ if (bs->backing_hd) bdrv_flush(bs->backing_hd); + +ro_cleanup: + + if (ro) { + /* re-open as RO */ + bdrv_delete(bs->backing_hd); + bs->backing_hd = NULL; + bs_ro = bdrv_new(""); + ret = bdrv_open2(bs_ro, filename, open_flags & ~BDRV_O_RDWR, NULL); + if (ret < 0) { + bdrv_delete(bs_ro); + /* drive not functional anymore */ + bs->drv = NULL; + return ret; + } + bs->backing_hd = bs_ro; + bs->backing_hd->keep_read_only = 0; + } + return ret; } diff --git a/block_int.h b/block_int.h index 930a5a4..50e1a0b 100644 --- a/block_int.h +++ b/block_int.h @@ -130,6 +130,8 @@ struct BlockDriverState { int64_t total_sectors; /* if we are reading a disk image, give its size in sectors */ int read_only; /* if true, the media is read only */ + int keep_read_only; /* if true, the media was requested to stay read only */ + int open_flags; /* flags used to open the file, re-used for re-open */ int removable; /* if true, the media can be removed */ int locked; /* if true, the media cannot temporarily be ejected */ int encrypted; /* if true, the media is encrypted */
Open backing file read-only where possible Upgrade backing file to read-write during commit, back to read-only after commit If upgrade fail, back to read-only. If also fail, "disconnect" the drive. Signed-off-by: Naphtali Sprei <nsprei@redhat.com> --- block.c | 83 ++++++++++++++++++++++++++++++++++++++++++++++++++-------- block_int.h | 2 + 2 files changed, 73 insertions(+), 12 deletions(-)