/* * CDDL HEADER START * * The contents of this file are subject to the terms of the * Common Development and Distribution License (the "License"). * You may not use this file except in compliance with the License. * * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE * or http://www.opensolaris.org/os/licensing. * See the License for the specific language governing permissions * and limitations under the License. * * When distributing Covered Code, include this CDDL HEADER in each * file and include the License file at usr/src/OPENSOLARIS.LICENSE. * If applicable, add the following below this CDDL HEADER, with the * fields enclosed by brackets "[]" replaced with your own identifying * information: Portions Copyright [yyyy] [name of copyright owner] * * CDDL HEADER END */ /* * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved. * Copyright (c) 2012, 2018 by Delphix. All rights reserved. * Copyright (c) 2015 by Chunwei Chen. All rights reserved. * Copyright 2017 Nexenta Systems, Inc. */ /* Portions Copyright 2007 Jeremy Teo */ /* Portions Copyright 2010 Robert Milkowski */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include static ulong_t zfs_fsync_sync_cnt = 4; int zfs_fsync(znode_t *zp, int syncflag, cred_t *cr) { zfsvfs_t *zfsvfs = ZTOZSB(zp); (void) tsd_set(zfs_fsyncer_key, (void *)zfs_fsync_sync_cnt); if (zfsvfs->z_os->os_sync != ZFS_SYNC_DISABLED) { ZFS_ENTER(zfsvfs); ZFS_VERIFY_ZP(zp); atomic_inc_32(&zp->z_sync_writes_cnt); zil_commit(zfsvfs->z_log, zp->z_id); atomic_dec_32(&zp->z_sync_writes_cnt); ZFS_EXIT(zfsvfs); } tsd_set(zfs_fsyncer_key, NULL); return (0); } #if defined(SEEK_HOLE) && defined(SEEK_DATA) /* * Lseek support for finding holes (cmd == SEEK_HOLE) and * data (cmd == SEEK_DATA). "off" is an in/out parameter. */ static int zfs_holey_common(znode_t *zp, ulong_t cmd, loff_t *off) { zfs_locked_range_t *lr; uint64_t noff = (uint64_t)*off; /* new offset */ uint64_t file_sz; int error; boolean_t hole; file_sz = zp->z_size; if (noff >= file_sz) { return (SET_ERROR(ENXIO)); } if (cmd == F_SEEK_HOLE) hole = B_TRUE; else hole = B_FALSE; /* Flush any mmap()'d data to disk */ if (zn_has_cached_data(zp)) zn_flush_cached_data(zp, B_FALSE); lr = zfs_rangelock_enter(&zp->z_rangelock, 0, file_sz, RL_READER); error = dmu_offset_next(ZTOZSB(zp)->z_os, zp->z_id, hole, &noff); zfs_rangelock_exit(lr); if (error == ESRCH) return (SET_ERROR(ENXIO)); /* File was dirty, so fall back to using generic logic */ if (error == EBUSY) { if (hole) *off = file_sz; return (0); } /* * We could find a hole that begins after the logical end-of-file, * because dmu_offset_next() only works on whole blocks. If the * EOF falls mid-block, then indicate that the "virtual hole" * at the end of the file begins at the logical EOF, rather than * at the end of the last block. */ if (noff > file_sz) { ASSERT(hole); noff = file_sz; } if (noff < *off) return (error); *off = noff; return (error); } int zfs_holey(znode_t *zp, ulong_t cmd, loff_t *off) { zfsvfs_t *zfsvfs = ZTOZSB(zp); int error; ZFS_ENTER(zfsvfs); ZFS_VERIFY_ZP(zp); error = zfs_holey_common(zp, cmd, off); ZFS_EXIT(zfsvfs); return (error); } #endif /* SEEK_HOLE && SEEK_DATA */ int zfs_access(znode_t *zp, int mode, int flag, cred_t *cr) { zfsvfs_t *zfsvfs = ZTOZSB(zp); int error; ZFS_ENTER(zfsvfs); ZFS_VERIFY_ZP(zp); if (flag & V_ACE_MASK) error = zfs_zaccess(zp, mode, flag, B_FALSE, cr); else error = zfs_zaccess_rwx(zp, mode, flag, cr); ZFS_EXIT(zfsvfs); return (error); } static unsigned long zfs_vnops_read_chunk_size = 1024 * 1024; /* Tunable */ /* * Read bytes from specified file into supplied buffer. * * IN: zp - inode of file to be read from. * uio - structure supplying read location, range info, * and return buffer. * ioflag - O_SYNC flags; used to provide FRSYNC semantics. * O_DIRECT flag; used to bypass page cache. * cr - credentials of caller. * * OUT: uio - updated offset and range, buffer filled. * * RETURN: 0 on success, error code on failure. * * Side Effects: * inode - atime updated if byte count > 0 */ int zfs_read(struct znode *zp, zfs_uio_t *uio, int ioflag, cred_t *cr) { (void) cr; int error = 0; boolean_t frsync = B_FALSE; zfsvfs_t *zfsvfs = ZTOZSB(zp); ZFS_ENTER(zfsvfs); ZFS_VERIFY_ZP(zp); if (zp->z_pflags & ZFS_AV_QUARANTINED) { ZFS_EXIT(zfsvfs); return (SET_ERROR(EACCES)); } /* We don't copy out anything useful for directories. */ if (Z_ISDIR(ZTOTYPE(zp))) { ZFS_EXIT(zfsvfs); return (SET_ERROR(EISDIR)); } /* * Validate file offset */ if (zfs_uio_offset(uio) < (offset_t)0) { ZFS_EXIT(zfsvfs); return (SET_ERROR(EINVAL)); } /* * Fasttrack empty reads */ if (zfs_uio_resid(uio) == 0) { ZFS_EXIT(zfsvfs); return (0); } #ifdef FRSYNC /* * If we're in FRSYNC mode, sync out this znode before reading it. * Only do this for non-snapshots. * * Some platforms do not support FRSYNC and instead map it * to O_SYNC, which results in unnecessary calls to zil_commit. We * only honor FRSYNC requests on platforms which support it. */ frsync = !!(ioflag & FRSYNC); #endif if (zfsvfs->z_log && (frsync || zfsvfs->z_os->os_sync == ZFS_SYNC_ALWAYS)) zil_commit(zfsvfs->z_log, zp->z_id); /* * Lock the range against changes. */ zfs_locked_range_t *lr = zfs_rangelock_enter(&zp->z_rangelock, zfs_uio_offset(uio), zfs_uio_resid(uio), RL_READER); /* * If we are reading past end-of-file we can skip * to the end; but we might still need to set atime. */ if (zfs_uio_offset(uio) >= zp->z_size) { error = 0; goto out; } ASSERT(zfs_uio_offset(uio) < zp->z_size); #if defined(__linux__) ssize_t start_offset = zfs_uio_offset(uio); #endif ssize_t n = MIN(zfs_uio_resid(uio), zp->z_size - zfs_uio_offset(uio)); ssize_t start_resid = n; while (n > 0) { ssize_t nbytes = MIN(n, zfs_vnops_read_chunk_size - P2PHASE(zfs_uio_offset(uio), zfs_vnops_read_chunk_size)); #ifdef UIO_NOCOPY if (zfs_uio_segflg(uio) == UIO_NOCOPY) error = mappedread_sf(zp, nbytes, uio); else #endif if (zn_has_cached_data(zp) && !(ioflag & O_DIRECT)) { error = mappedread(zp, nbytes, uio); } else { error = dmu_read_uio_dbuf(sa_get_db(zp->z_sa_hdl), uio, nbytes); } if (error) { /* convert checksum errors into IO errors */ if (error == ECKSUM) error = SET_ERROR(EIO); #if defined(__linux__) /* * if we actually read some bytes, bubbling EFAULT * up to become EAGAIN isn't what we want here... * * ...on Linux, at least. On FBSD, doing this breaks. */ if (error == EFAULT && (zfs_uio_offset(uio) - start_offset) != 0) error = 0; #endif break; } n -= nbytes; } int64_t nread = start_resid - n; dataset_kstats_update_read_kstats(&zfsvfs->z_kstat, nread); task_io_account_read(nread); out: zfs_rangelock_exit(lr); ZFS_ACCESSTIME_STAMP(zfsvfs, zp); ZFS_EXIT(zfsvfs); return (error); } static void zfs_clear_setid_bits_if_necessary(zfsvfs_t *zfsvfs, znode_t *zp, cred_t *cr, uint64_t *clear_setid_bits_txgp, dmu_tx_t *tx) { zilog_t *zilog = zfsvfs->z_log; const uint64_t uid = KUID_TO_SUID(ZTOUID(zp)); ASSERT(clear_setid_bits_txgp != NULL); ASSERT(tx != NULL); /* * Clear Set-UID/Set-GID bits on successful write if not * privileged and at least one of the execute bits is set. * * It would be nice to do this after all writes have * been done, but that would still expose the ISUID/ISGID * to another app after the partial write is committed. * * Note: we don't call zfs_fuid_map_id() here because * user 0 is not an ephemeral uid. */ mutex_enter(&zp->z_acl_lock); if ((zp->z_mode & (S_IXUSR | (S_IXUSR >> 3) | (S_IXUSR >> 6))) != 0 && (zp->z_mode & (S_ISUID | S_ISGID)) != 0 && secpolicy_vnode_setid_retain(zp, cr, ((zp->z_mode & S_ISUID) != 0 && uid == 0)) != 0) { uint64_t newmode; zp->z_mode &= ~(S_ISUID | S_ISGID); newmode = zp->z_mode; (void) sa_update(zp->z_sa_hdl, SA_ZPL_MODE(zfsvfs), (void *)&newmode, sizeof (uint64_t), tx); mutex_exit(&zp->z_acl_lock); /* * Make sure SUID/SGID bits will be removed when we replay the * log. If the setid bits are keep coming back, don't log more * than one TX_SETATTR per transaction group. */ if (*clear_setid_bits_txgp != dmu_tx_get_txg(tx)) { vattr_t va = {0}; va.va_mask = ATTR_MODE; va.va_nodeid = zp->z_id; va.va_mode = newmode; zfs_log_setattr(zilog, tx, TX_SETATTR, zp, &va, ATTR_MODE, NULL); *clear_setid_bits_txgp = dmu_tx_get_txg(tx); } } else { mutex_exit(&zp->z_acl_lock); } } /* * Write the bytes to a file. * * IN: zp - znode of file to be written to. * uio - structure supplying write location, range info, * and data buffer. * ioflag - O_APPEND flag set if in append mode. * O_DIRECT flag; used to bypass page cache. * cr - credentials of caller. * * OUT: uio - updated offset and range. * * RETURN: 0 if success * error code if failure * * Timestamps: * ip - ctime|mtime updated if byte count > 0 */ int zfs_write(znode_t *zp, zfs_uio_t *uio, int ioflag, cred_t *cr) { int error = 0, error1; ssize_t start_resid = zfs_uio_resid(uio); uint64_t clear_setid_bits_txg = 0; /* * Fasttrack empty write */ ssize_t n = start_resid; if (n == 0) return (0); zfsvfs_t *zfsvfs = ZTOZSB(zp); ZFS_ENTER(zfsvfs); ZFS_VERIFY_ZP(zp); sa_bulk_attr_t bulk[4]; int count = 0; uint64_t mtime[2], ctime[2]; SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_MTIME(zfsvfs), NULL, &mtime, 16); SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_CTIME(zfsvfs), NULL, &ctime, 16); SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_SIZE(zfsvfs), NULL, &zp->z_size, 8); SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_FLAGS(zfsvfs), NULL, &zp->z_pflags, 8); /* * Callers might not be able to detect properly that we are read-only, * so check it explicitly here. */ if (zfs_is_readonly(zfsvfs)) { ZFS_EXIT(zfsvfs); return (SET_ERROR(EROFS)); } /* * If immutable or not appending then return EPERM. * Intentionally allow ZFS_READONLY through here. * See zfs_zaccess_common() */ if ((zp->z_pflags & ZFS_IMMUTABLE) || ((zp->z_pflags & ZFS_APPENDONLY) && !(ioflag & O_APPEND) && (zfs_uio_offset(uio) < zp->z_size))) { ZFS_EXIT(zfsvfs); return (SET_ERROR(EPERM)); } /* * Validate file offset */ offset_t woff = ioflag & O_APPEND ? zp->z_size : zfs_uio_offset(uio); if (woff < 0) { ZFS_EXIT(zfsvfs); return (SET_ERROR(EINVAL)); } const uint64_t max_blksz = zfsvfs->z_max_blksz; /* * Pre-fault the pages to ensure slow (eg NFS) pages * don't hold up txg. * Skip this if uio contains loaned arc_buf. */ if (zfs_uio_prefaultpages(MIN(n, max_blksz), uio)) { ZFS_EXIT(zfsvfs); return (SET_ERROR(EFAULT)); } /* * If in append mode, set the io offset pointer to eof. */ zfs_locked_range_t *lr; if (ioflag & O_APPEND) { /* * Obtain an appending range lock to guarantee file append * semantics. We reset the write offset once we have the lock. */ lr = zfs_rangelock_enter(&zp->z_rangelock, 0, n, RL_APPEND); woff = lr->lr_offset; if (lr->lr_length == UINT64_MAX) { /* * We overlocked the file because this write will cause * the file block size to increase. * Note that zp_size cannot change with this lock held. */ woff = zp->z_size; } zfs_uio_setoffset(uio, woff); } else { /* * Note that if the file block size will change as a result of * this write, then this range lock will lock the entire file * so that we can re-write the block safely. */ lr = zfs_rangelock_enter(&zp->z_rangelock, woff, n, RL_WRITER); } if (zn_rlimit_fsize(zp, uio)) { zfs_rangelock_exit(lr); ZFS_EXIT(zfsvfs); return (SET_ERROR(EFBIG)); } const rlim64_t limit = MAXOFFSET_T; if (woff >= limit) { zfs_rangelock_exit(lr); ZFS_EXIT(zfsvfs); return (SET_ERROR(EFBIG)); } if (n > limit - woff) n = limit - woff; uint64_t end_size = MAX(zp->z_size, woff + n); zilog_t *zilog = zfsvfs->z_log; const uint64_t uid = KUID_TO_SUID(ZTOUID(zp)); const uint64_t gid = KGID_TO_SGID(ZTOGID(zp)); const uint64_t projid = zp->z_projid; /* * Write the file in reasonable size chunks. Each chunk is written * in a separate transaction; this keeps the intent log records small * and allows us to do more fine-grained space accounting. */ while (n > 0) { woff = zfs_uio_offset(uio); if (zfs_id_overblockquota(zfsvfs, DMU_USERUSED_OBJECT, uid) || zfs_id_overblockquota(zfsvfs, DMU_GROUPUSED_OBJECT, gid) || (projid != ZFS_DEFAULT_PROJID && zfs_id_overblockquota(zfsvfs, DMU_PROJECTUSED_OBJECT, projid))) { error = SET_ERROR(EDQUOT); break; } arc_buf_t *abuf = NULL; if (n >= max_blksz && woff >= zp->z_size && P2PHASE(woff, max_blksz) == 0 && zp->z_blksz == max_blksz) { /* * This write covers a full block. "Borrow" a buffer * from the dmu so that we can fill it before we enter * a transaction. This avoids the possibility of * holding up the transaction if the data copy hangs * up on a pagefault (e.g., from an NFS server mapping). */ size_t cbytes; abuf = dmu_request_arcbuf(sa_get_db(zp->z_sa_hdl), max_blksz); ASSERT(abuf != NULL); ASSERT(arc_buf_size(abuf) == max_blksz); if ((error = zfs_uiocopy(abuf->b_data, max_blksz, UIO_WRITE, uio, &cbytes))) { dmu_return_arcbuf(abuf); break; } ASSERT3S(cbytes, ==, max_blksz); } /* * Start a transaction. */ dmu_tx_t *tx = dmu_tx_create(zfsvfs->z_os); dmu_tx_hold_sa(tx, zp->z_sa_hdl, B_FALSE); dmu_buf_impl_t *db = (dmu_buf_impl_t *)sa_get_db(zp->z_sa_hdl); DB_DNODE_ENTER(db); dmu_tx_hold_write_by_dnode(tx, DB_DNODE(db), woff, MIN(n, max_blksz)); DB_DNODE_EXIT(db); zfs_sa_upgrade_txholds(tx, zp); error = dmu_tx_assign(tx, TXG_WAIT); if (error) { dmu_tx_abort(tx); if (abuf != NULL) dmu_return_arcbuf(abuf); break; } /* * NB: We must call zfs_clear_setid_bits_if_necessary before * committing the transaction! */ /* * If rangelock_enter() over-locked we grow the blocksize * and then reduce the lock range. This will only happen * on the first iteration since rangelock_reduce() will * shrink down lr_length to the appropriate size. */ if (lr->lr_length == UINT64_MAX) { uint64_t new_blksz; if (zp->z_blksz > max_blksz) { /* * File's blocksize is already larger than the * "recordsize" property. Only let it grow to * the next power of 2. */ ASSERT(!ISP2(zp->z_blksz)); new_blksz = MIN(end_size, 1 << highbit64(zp->z_blksz)); } else { new_blksz = MIN(end_size, max_blksz); } zfs_grow_blocksize(zp, new_blksz, tx); zfs_rangelock_reduce(lr, woff, n); } /* * XXX - should we really limit each write to z_max_blksz? * Perhaps we should use SPA_MAXBLOCKSIZE chunks? */ const ssize_t nbytes = MIN(n, max_blksz - P2PHASE(woff, max_blksz)); ssize_t tx_bytes; if (abuf == NULL) { tx_bytes = zfs_uio_resid(uio); zfs_uio_fault_disable(uio, B_TRUE); error = dmu_write_uio_dbuf(sa_get_db(zp->z_sa_hdl), uio, nbytes, tx); zfs_uio_fault_disable(uio, B_FALSE); #ifdef __linux__ if (error == EFAULT) { zfs_clear_setid_bits_if_necessary(zfsvfs, zp, cr, &clear_setid_bits_txg, tx); dmu_tx_commit(tx); /* * Account for partial writes before * continuing the loop. * Update needs to occur before the next * zfs_uio_prefaultpages, or prefaultpages may * error, and we may break the loop early. */ if (tx_bytes != zfs_uio_resid(uio)) n -= tx_bytes - zfs_uio_resid(uio); if (zfs_uio_prefaultpages(MIN(n, max_blksz), uio)) { break; } continue; } #endif /* * On FreeBSD, EFAULT should be propagated back to the * VFS, which will handle faulting and will retry. */ if (error != 0 && error != EFAULT) { zfs_clear_setid_bits_if_necessary(zfsvfs, zp, cr, &clear_setid_bits_txg, tx); dmu_tx_commit(tx); break; } tx_bytes -= zfs_uio_resid(uio); } else { /* Implied by abuf != NULL: */ ASSERT3S(n, >=, max_blksz); ASSERT0(P2PHASE(woff, max_blksz)); /* * We can simplify nbytes to MIN(n, max_blksz) since * P2PHASE(woff, max_blksz) is 0, and knowing * n >= max_blksz lets us simplify further: */ ASSERT3S(nbytes, ==, max_blksz); /* * Thus, we're writing a full block at a block-aligned * offset and extending the file past EOF. * * dmu_assign_arcbuf_by_dbuf() will directly assign the * arc buffer to a dbuf. */ error = dmu_assign_arcbuf_by_dbuf( sa_get_db(zp->z_sa_hdl), woff, abuf, tx); if (error != 0) { /* * XXX This might not be necessary if * dmu_assign_arcbuf_by_dbuf is guaranteed * to be atomic. */ zfs_clear_setid_bits_if_necessary(zfsvfs, zp, cr, &clear_setid_bits_txg, tx); dmu_return_arcbuf(abuf); dmu_tx_commit(tx); break; } ASSERT3S(nbytes, <=, zfs_uio_resid(uio)); zfs_uioskip(uio, nbytes); tx_bytes = nbytes; } if (tx_bytes && zn_has_cached_data(zp) && !(ioflag & O_DIRECT)) { update_pages(zp, woff, tx_bytes, zfsvfs->z_os); } /* * If we made no progress, we're done. If we made even * partial progress, update the znode and ZIL accordingly. */ if (tx_bytes == 0) { (void) sa_update(zp->z_sa_hdl, SA_ZPL_SIZE(zfsvfs), (void *)&zp->z_size, sizeof (uint64_t), tx); dmu_tx_commit(tx); ASSERT(error != 0); break; } zfs_clear_setid_bits_if_necessary(zfsvfs, zp, cr, &clear_setid_bits_txg, tx); zfs_tstamp_update_setup(zp, CONTENT_MODIFIED, mtime, ctime); /* * Update the file size (zp_size) if it has changed; * account for possible concurrent updates. */ while ((end_size = zp->z_size) < zfs_uio_offset(uio)) { (void) atomic_cas_64(&zp->z_size, end_size, zfs_uio_offset(uio)); ASSERT(error == 0 || error == EFAULT); } /* * If we are replaying and eof is non zero then force * the file size to the specified eof. Note, there's no * concurrency during replay. */ if (zfsvfs->z_replay && zfsvfs->z_replay_eof != 0) zp->z_size = zfsvfs->z_replay_eof; error1 = sa_bulk_update(zp->z_sa_hdl, bulk, count, tx); if (error1 != 0) /* Avoid clobbering EFAULT. */ error = error1; /* * NB: During replay, the TX_SETATTR record logged by * zfs_clear_setid_bits_if_necessary must precede any of * the TX_WRITE records logged here. */ zfs_log_write(zilog, tx, TX_WRITE, zp, woff, tx_bytes, ioflag, NULL, NULL); dmu_tx_commit(tx); if (error != 0) break; ASSERT3S(tx_bytes, ==, nbytes); n -= nbytes; if (n > 0) { if (zfs_uio_prefaultpages(MIN(n, max_blksz), uio)) { error = SET_ERROR(EFAULT); break; } } } zfs_znode_update_vfs(zp); zfs_rangelock_exit(lr); /* * If we're in replay mode, or we made no progress, or the * uio data is inaccessible return an error. Otherwise, it's * at least a partial write, so it's successful. */ if (zfsvfs->z_replay || zfs_uio_resid(uio) == start_resid || error == EFAULT) { ZFS_EXIT(zfsvfs); return (error); } if (ioflag & (O_SYNC | O_DSYNC) || zfsvfs->z_os->os_sync == ZFS_SYNC_ALWAYS) zil_commit(zilog, zp->z_id); const int64_t nwritten = start_resid - zfs_uio_resid(uio); dataset_kstats_update_write_kstats(&zfsvfs->z_kstat, nwritten); task_io_account_write(nwritten); ZFS_EXIT(zfsvfs); return (0); } int zfs_getsecattr(znode_t *zp, vsecattr_t *vsecp, int flag, cred_t *cr) { zfsvfs_t *zfsvfs = ZTOZSB(zp); int error; boolean_t skipaclchk = (flag & ATTR_NOACLCHECK) ? B_TRUE : B_FALSE; ZFS_ENTER(zfsvfs); ZFS_VERIFY_ZP(zp); error = zfs_getacl(zp, vsecp, skipaclchk, cr); ZFS_EXIT(zfsvfs); return (error); } int zfs_setsecattr(znode_t *zp, vsecattr_t *vsecp, int flag, cred_t *cr) { zfsvfs_t *zfsvfs = ZTOZSB(zp); int error; boolean_t skipaclchk = (flag & ATTR_NOACLCHECK) ? B_TRUE : B_FALSE; zilog_t *zilog = zfsvfs->z_log; ZFS_ENTER(zfsvfs); ZFS_VERIFY_ZP(zp); error = zfs_setacl(zp, vsecp, skipaclchk, cr); if (zfsvfs->z_os->os_sync == ZFS_SYNC_ALWAYS) zil_commit(zilog, 0); ZFS_EXIT(zfsvfs); return (error); } #ifdef ZFS_DEBUG static int zil_fault_io = 0; #endif static void zfs_get_done(zgd_t *zgd, int error); /* * Get data to generate a TX_WRITE intent log record. */ int zfs_get_data(void *arg, uint64_t gen, lr_write_t *lr, char *buf, struct lwb *lwb, zio_t *zio) { zfsvfs_t *zfsvfs = arg; objset_t *os = zfsvfs->z_os; znode_t *zp; uint64_t object = lr->lr_foid; uint64_t offset = lr->lr_offset; uint64_t size = lr->lr_length; dmu_buf_t *db; zgd_t *zgd; int error = 0; uint64_t zp_gen; ASSERT3P(lwb, !=, NULL); ASSERT3P(zio, !=, NULL); ASSERT3U(size, !=, 0); /* * Nothing to do if the file has been removed */ if (zfs_zget(zfsvfs, object, &zp) != 0) return (SET_ERROR(ENOENT)); if (zp->z_unlinked) { /* * Release the vnode asynchronously as we currently have the * txg stopped from syncing. */ zfs_zrele_async(zp); return (SET_ERROR(ENOENT)); } /* check if generation number matches */ if (sa_lookup(zp->z_sa_hdl, SA_ZPL_GEN(zfsvfs), &zp_gen, sizeof (zp_gen)) != 0) { zfs_zrele_async(zp); return (SET_ERROR(EIO)); } if (zp_gen != gen) { zfs_zrele_async(zp); return (SET_ERROR(ENOENT)); } zgd = (zgd_t *)kmem_zalloc(sizeof (zgd_t), KM_SLEEP); zgd->zgd_lwb = lwb; zgd->zgd_private = zp; /* * Write records come in two flavors: immediate and indirect. * For small writes it's cheaper to store the data with the * log record (immediate); for large writes it's cheaper to * sync the data and get a pointer to it (indirect) so that * we don't have to write the data twice. */ if (buf != NULL) { /* immediate write */ zgd->zgd_lr = zfs_rangelock_enter(&zp->z_rangelock, offset, size, RL_READER); /* test for truncation needs to be done while range locked */ if (offset >= zp->z_size) { error = SET_ERROR(ENOENT); } else { error = dmu_read(os, object, offset, size, buf, DMU_READ_NO_PREFETCH); } ASSERT(error == 0 || error == ENOENT); } else { /* indirect write */ /* * Have to lock the whole block to ensure when it's * written out and its checksum is being calculated * that no one can change the data. We need to re-check * blocksize after we get the lock in case it's changed! */ for (;;) { uint64_t blkoff; size = zp->z_blksz; blkoff = ISP2(size) ? P2PHASE(offset, size) : offset; offset -= blkoff; zgd->zgd_lr = zfs_rangelock_enter(&zp->z_rangelock, offset, size, RL_READER); if (zp->z_blksz == size) break; offset += blkoff; zfs_rangelock_exit(zgd->zgd_lr); } /* test for truncation needs to be done while range locked */ if (lr->lr_offset >= zp->z_size) error = SET_ERROR(ENOENT); #ifdef ZFS_DEBUG if (zil_fault_io) { error = SET_ERROR(EIO); zil_fault_io = 0; } #endif if (error == 0) error = dmu_buf_hold(os, object, offset, zgd, &db, DMU_READ_NO_PREFETCH); if (error == 0) { blkptr_t *bp = &lr->lr_blkptr; zgd->zgd_db = db; zgd->zgd_bp = bp; ASSERT(db->db_offset == offset); ASSERT(db->db_size == size); error = dmu_sync(zio, lr->lr_common.lrc_txg, zfs_get_done, zgd); ASSERT(error || lr->lr_length <= size); /* * On success, we need to wait for the write I/O * initiated by dmu_sync() to complete before we can * release this dbuf. We will finish everything up * in the zfs_get_done() callback. */ if (error == 0) return (0); if (error == EALREADY) { lr->lr_common.lrc_txtype = TX_WRITE2; /* * TX_WRITE2 relies on the data previously * written by the TX_WRITE that caused * EALREADY. We zero out the BP because * it is the old, currently-on-disk BP. */ zgd->zgd_bp = NULL; BP_ZERO(bp); error = 0; } } } zfs_get_done(zgd, error); return (error); } static void zfs_get_done(zgd_t *zgd, int error) { (void) error; znode_t *zp = zgd->zgd_private; if (zgd->zgd_db) dmu_buf_rele(zgd->zgd_db, zgd); zfs_rangelock_exit(zgd->zgd_lr); /* * Release the vnode asynchronously as we currently have the * txg stopped from syncing. */ zfs_zrele_async(zp); kmem_free(zgd, sizeof (zgd_t)); } EXPORT_SYMBOL(zfs_access); EXPORT_SYMBOL(zfs_fsync); EXPORT_SYMBOL(zfs_holey); EXPORT_SYMBOL(zfs_read); EXPORT_SYMBOL(zfs_write); EXPORT_SYMBOL(zfs_getsecattr); EXPORT_SYMBOL(zfs_setsecattr); ZFS_MODULE_PARAM(zfs_vnops, zfs_vnops_, read_chunk_size, ULONG, ZMOD_RW, "Bytes to read per chunk");